Stand Up for Jesus 
Here are some wonderful words of a beautiful and popular hymn, sung by most people who have ever attended church on a fairly regular basis: 
Stand up! Stand up for Jesus!
Ye soldiers of the cross;
Lift high His royal banner,
It must not suffer loss;
From victory unto victory
His army shall He lead,
Till every foe is vanquished,
And Christ is Lord indeed.
Stand up! Stand up for Jesus!
The trumpet call obey;
Forth to the mighty conflict
In this His glorious day!
Ye that are men now serve Him,
Against unnumbered foes;
Let courage rise with danger,
And strength to strength oppose.
Stand up! Stand up for Jesus!
Stand in His strength alone:
The arm of flesh shall fail you -
Ye dare not trust your own:
Put on the gospel armour,
And, watching unto prayer,
Where duty calls, or danger,
Be never wanting there.
Stand up! Stand up for Jesus!
The strife will not be long;
This day the noise of battle,
The next the victor's song;
To him that overcometh
A crown of life shall be;
He with the King of glory
Shall reign eternally.
Another, just as popular, if one can judge by the enthusiasm of the singers in church:
Onward Christian soldiers! marching as to war,
Looking unto Jesus, who is gone before.
Christ, the Royal Master, leads against the foe;
Forward into battle see His banners go.
When it comes to putting into practice what is sung about, it may be another matter entirely. 
The Lord God, by His only begotten Son and His Holy Spirit, has shown us through His word, all that we need in defending ourselves and defeating the enemy. And using all to stand: 
Finally, my brethren, be strong in the Lord, and in the power of his might. Put on the whole armour of God, that ye may be able to stand against the wiles of the devil. For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand. Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness; And your feet shod with the preparation of the gospel of peace; Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. And take the helmet of salvation, and the sword of the Spirit, which is the word of God: Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints; 
(Ephesians 6:10-18)
How many of us actively follow what we sing and read about - how obedient are we to our Master's voice? 
Here's a little story that has some element of truth as its basis that should emphasise what is meant: 
Two elderly couples shared a semidetached dwelling unit in a housing complex for retired people. In the course of time the men and the ladies became friends as well as neighbours and many pleasant hours were spent on each other's verandas in the summer evenings and interesting discussions were held. Sometimes it happened that the ladies would be in one place and the men in another and on one of these occasions it was discovered that both men were professing Christians. 
The one had been brought up at his mother's knee to learn about Jesus Christ and was, after many decades, still a devout church attendee, reading his Bible every day. 
The other had been brought up in a devout household, grew up in a church boarding school and couldn't understand what all the fuss was about. Why was it necessary for Jesus to die to save him - why not just do it? Then one day he came spiritual face to spiritual face with Jesus, who told him why the cross was necessary and he became converted. 
So, many evenings were spent discussing Christian matters, until a difference of opinion developed into the beginnings of an argument and this sensitive subject was never raised again. 
In the course of time both families agreed that certain alterations were necessary to the building and that one day in the uncertain future something would have to be done about it. On a certain day, without consulting the other, each man telephoned the same contractor to obtain a quotation for the work to be done. On agreeing to the costs, the work went ahead and when it came time to pay, it was suggested by the contractor that payment could be made in cash as this would bypass the necessity of paying value added tax. The one householder paid cash for his share of the work and the other insisted on paying the relevant VAT together with his share. 
You know why don't you?
The one man had been converted from living in this temporary worldly kingdom of Satan to the glorious eternal kingdom of God's Son. He knew Jesus, and he knew that his Master would not approve. 
Let's see what the Bible has to say on the subject: 
As an introduction, you shall see from the following, and comparing Paul's words of greeting with, say, those in the beginning of Corinthians, that Paul believed the Thessalonian churches to be more Christ-like than many. 
Paul, and Silvanus, and Timotheus, unto the church of the Thessalonians which is in God the Father and in the Lord Jesus Christ: Grace be unto you, and peace, from God our Father, and the Lord Jesus Christ. We give thanks to God always for you all, making mention of you in our prayers; Remembering without ceasing your work of faith, and labour of love, and patience of hope in our Lord Jesus Christ, in the sight of God and our Father; Knowing, brethren beloved, your election of God. For our gospel came not unto you in word only, but also in power, and in the Holy Ghost, and in much assurance; as ye know what manner of men we were among you for your sake. And ye became followers of us, and of the Lord, having received the word in much affliction, with joy of the Holy Ghost: So that ye were ensamples to all that believe in Macedonia and Achaia. For from you sounded out the word of the Lord not only in Macedonia and Achaia, but also in every place your faith to God-ward is spread abroad; so that we need not to speak any thing. For they themselves shew of us what manner of entering in we had unto you, and how ye turned to God from idols to serve the living and true God; And to wait for his Son from heaven, whom he raised from the dead, even Jesus, which delivered us from the wrath to come. 
(1 Thessalonians 1:1-10)
Nevertheless, he was still concerned because, unlike Corinth and Ephesus, he had not spent much time there: 
Now when they had passed through Amphipolis and Apollonia, they came to Thessalonica, where was a synagogue of the Jews: And Paul, as his manner was, went in unto them, and three sabbath days reasoned with them out of the scriptures, Opening and alleging, that Christ must needs have suffered, and risen again from the dead; and that this Jesus, whom I preach unto you, is Christ. And some of them believed, and consorted with Paul and Silas; and of the devout Greeks a great multitude, and of the chief women not a few. But the Jews which believed not, moved with envy, took unto them certain lewd fellows of the baser sort, and gathered a company, and set all the city on an uproar, and assaulted the house of Jason, and sought to bring them out to the people. And when they found them not, they drew Jason and certain brethren unto the rulers of the city, crying, These that have turned the world upside down are come hither also; Whom Jason hath received: and these all do contrary to the decrees of Caesar, saying that there is another king, one Jesus. And they troubled the people and the rulers of the city, when they heard these things. And when they had taken security of Jason, and of the other, they let them go. And the brethren immediately sent away Paul and Silas by night unto Berea: who coming thither went into the synagogue of the Jews. These were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so. Therefore many of them believed; also of honourable women which were Greeks, and of men, not a few. But when the Jews of Thessalonica had knowledge that the word of God was preached of Paul at Berea, they came thither also, and stirred up the people. And then immediately the brethren sent away Paul to go as it were to the sea: but Silas and Timotheus abode there still. And they that conducted Paul brought him unto Athens: and receiving a commandment unto Silas and Timotheus for to come to him with all speed, they departed. 
(Acts 17:1-15)
But even after that we had suffered before, and were shamefully entreated, as ye know, at Philippi, we were bold in our God to speak unto you the gospel of God with much contention. For our exhortation was not of deceit, nor of uncleanness, nor in guile: But as we were allowed of God to be put in trust with the gospel, even so we speak; not as pleasing men, but God, which trieth our hearts. For neither at any time used we flattering words, as ye know, nor a cloke of covetousness; God is witness: Nor of men sought we glory, neither of you, nor yet of others, when we might have been burdensome, as the apostles of Christ. But we were gentle among you, even as a nurse cherisheth her children: So being affectionately desirous of you, we were willing to have imparted unto you, not the gospel of God only, but also our own souls, because ye were dear unto us. For ye remember, brethren, our labour and travail: for labouring night and day, because we would not be chargeable unto any of you, we preached unto you the gospel of God. Ye are witnesses, and God also, how holily and justly and unblameably we behaved ourselves among you that believe: As ye know how we exhorted and comforted and charged every one of you, as a father doth his children, That ye would walk worthy of God, who hath called you unto his kingdom and glory. For this cause also thank we God without ceasing, because, when ye received the word of God which ye heard of us, ye received it not as the word of men, but as it is in truth, the word of God, which effectually worketh also in you that believe. For ye, brethren, became followers of the churches of God which in Judaea are in Christ Jesus: for ye also have suffered like things of your own countrymen, even as they have of the Jews: Who both killed the Lord Jesus, and their own prophets, and have persecuted us; and they please not God, and are contrary to all men: Forbidding us to speak to the Gentiles that they might be saved, to fill up their sins alway: for the wrath is come upon them to the uttermost. But we, brethren, being taken from you for a short time in presence, not in heart, endeavoured the more abundantly to see your face with great desire. Wherefore we would have come unto you, even I Paul, once and again; but Satan hindered us. For what is our hope, or joy, or crown of rejoicing? Are not even ye in the presence of our Lord Jesus Christ at his coming? For ye are our glory and joy. Wherefore when we could no longer forbear, we thought it good to be left at Athens alone; And sent Timotheus, our brother, and minister of God, and our fellowlabourer in the gospel of Christ, to establish you, and to comfort you concerning your faith: That no man should be moved by these afflictions: for yourselves know that we are appointed thereunto. For verily, when we were with you, we told you before that we should suffer tribulation; even as it came to pass, and ye know. For this cause, when I could no longer forbear, I sent to know your faith, lest by some means the tempter have tempted you, and our labour be in vain. But now when Timotheus came from you unto us, and brought us good tidings of your faith and charity, and that ye have good remembrance of us always, desiring greatly to see us, as we also to see you: Therefore, brethren, we were comforted over you in all our affliction and distress by your faith: For now we live, if ye stand fast in the Lord. 
(1 Thessalonians 2:2 - 3:8)
This is what Jesus said about being converted:
Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God. 
(John 3:3)
And the disciples came, and said unto him, Why speakest thou unto them in parables? He answered and said unto them, Because it is given unto you to know the mysteries of the kingdom of heaven, but to them it is not given. For whosoever hath, to him shall be given, and he shall have more abundance: but whosoever hath not, from him shall be taken away even that he hath. Therefore speak I to them in parables: because they seeing see not; and hearing they hear not, neither do they understand. And in them is fulfilled the prophecy of Esaias, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive: For this people's heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes, and hear with their ears, and should understand with their heart, and should be converted, and I should heal them. But blessed are your eyes, for they see: and your ears, for they hear. For verily I say unto you, That many prophets and righteous men have desired to see those things which ye see, and have not seen them; and to hear those things which ye hear, and have not heard them
(Matthew 13:10-17)
And the Lord said, Simon, Simon, behold, Satan hath desired to have you, that he may sift you as wheat: But I have prayed for thee, that thy faith fail not: and when thou art converted, strengthen thy brethren. And he said unto him, Lord, I am ready to go with thee, both into prison, and to death. And he said, I tell thee, Peter, the cock shall not crow this day, before that thou shalt thrice deny that thou knowest me. And he said unto them, When I sent you without purse, and scrip, and shoes, lacked ye any thing? And they said, Nothing. 
(Luke 22:31-35)
When a wheat grain is converted into a plant it cannot change back into a seed; the plant may die, but then all is lost. One day, its seeds will be harvested for the use of the reaper. Its main purpose in life is to grow more seeds. 
Also, a tares plant, although it looks like a wheat plant cannot produce seed of any use to the reaper. 
Going back to the words of those hymns as shown above, many people will cheerfully sing them in the environment of the church, but they shall only mean anything to those who know the Eternal Author. 
The soldier of the cross shall recognise another soldier of the cross in the way of his battle against the enemy, not by his uniform. 
Moreover, the Christian's actions shall seem foolish and be met by a shaking of the head or even unkind words by the unconverted. 
What also is so wonderful is the fact that the Christian soldier is a volunteer, he does it out of choice and not for money. He cannot help himself - he gives his all, knowing when he is better off, trusting his Commanding Officer. 
Now we exhort you, brethren, warn them that are unruly, comfort the feebleminded, support the weak, be patient toward all men. See that none render evil for evil unto any man; but ever follow that which is good, both among yourselves, and to all men. Rejoice evermore. Pray without ceasing. In every thing give thanks: for this is the will of God in Christ Jesus concerning you. Quench not the Spirit. Despise not prophesyings. Prove all things; hold fast that which is good. Abstain from all appearance of evil. And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ. Faithful is he that calleth you, who also will do it. 
(1 Thessalonians 5:14-24)
The grace of our Lord Jesus Christ be with you. Amen. 
(1 Thessalonians 5:28)