The Nub of God's Purpose 
Nub - The point or gist (of the matter).
Our Holy and Righteous God is filled with Lovingkindness and wants us to be with Him one day - holy and righteous too. 
Jesus came on to the earth in a human body in response to the loving Covenant with Father God, showing to us His Oneness with the Father in that He allowed Himself to be killed by those whom He created; to prove to us, when He was raised from the dead in His new body, that He believed, and also that the Heavenly Father was faithful to that Covenant. 
God the eternal Son left His Deity behind in heaven, knowing that His body was to be crucified. He did this for me! 
And for you, if you accept this precious gift.
Let this mind be in you, which was also in Christ Jesus: Who, being in the form of God, thought it not robbery to be equal with God: But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men: And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross. 
(Philippians 2:5-8)
Jesus came without knowing all the ins and outs of what He was to accomplish, but trusted that the Heavenly Father would fully inform Him thereof after He had already committed Himself to the prison of a worldly body. In other words, there was no question in His mind that He might be abandoned by His Covenant Partners. 
Saying, The Son of man must suffer many things, and be rejected of the elders and chief priests and scribes, and be slain, and be raised the third day. 
(Luke 9:22)
And it came to pass about an eight days after these sayings, he took Peter and John and James, and went up into a mountain to pray. And as he prayed, the fashion of his countenance was altered, and his raiment was white and glistering. And, behold, there talked with him two men, which were Moses and Elias: Who appeared in glory, and spake of his decease which he should accomplish at Jerusalem. But Peter and they that were with him were heavy with sleep: and when they were awake, they saw his glory, and the two men that stood with him. And it came to pass, as they departed from him, Peter said unto Jesus, Master, it is good for us to be here: and let us make three tabernacles; one for thee, and one for Moses, and one for Elias: not knowing what he said. While he thus spake, there came a cloud, and overshadowed them: and they feared as they entered into the cloud. And there came a voice out of the cloud, saying, This is my beloved Son: hear him. And when the voice was past, Jesus was found alone. And they kept it close, and told no man in those days any of those things which they had seen. 
(Luke 9:28-36)
Therefore Jesus showed us the Oneness of the Covenant, the Power thereof and what it accomplished. 
Jesus also showed us the Love that our heavenly triune God has for us in that They have gone to all this trouble to give us another chance for LIFE. 
The same power is offered to mankind if they are prepared to come into Covenant with the Godhead: 
To have the saving faith (belief) in what Jesus achieved for mankind: 
But when I saw that they walked not uprightly according to the truth of the gospel, I said unto Peter before them all, If thou, being a Jew, livest after the manner of Gentiles, and not as do the Jews, why compellest thou the Gentiles to live as do the Jews? We who are Jews by nature, and not sinners of the Gentiles, Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified. 
(Galatians 2:14-16)
To change their evil ways willingly and earnestly, crying out their remorse. 
To be reborn of the Holy Spirit.
We must believe in the faith of Jesus Christ, learning to practice what He teaches. 
This is an act of our wills (John 14:21). It's called walking on the narrow way, and we do it with a grateful heart. 
One thing is certain, whether you or I believe it or not. We shall do the following willingly and joyfully or, like Satan, unwillingly: 
Wherefore God also hath highly exalted him, and given him a name which is above every name: That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth; And that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father. 
(Philippians 2:9-11)
This is in fulfilment of God's word to the Psalmist, and which Jesus of Nazareth used against the Pharisees: 
*A Psalm of David.* The LORD said unto my Lord, Sit thou at my right hand, until I make thine enemies thy footstool. The LORD shall send the rod of thy strength out of Zion: rule thou in the midst of thine enemies. Thy people shall be willing in the day of thy power, in the beauties of holiness from the womb of the morning: thou hast the dew of thy youth. The LORD hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek. The Lord at thy right hand shall strike through kings in the day of his wrath. He shall judge among the heathen, he shall fill the places with the dead bodies; he shall wound the heads over many countries. He shall drink of the brook in the way: therefore shall he lift up the head. 
(Psalms 110:1-7)
The one result that is self evident is that the power of death has been taken out of Satan's hands because we have been offered everlasting life with our Saviour: 
Now if Christ be preached that he rose from the dead, how say some among you that there is no resurrection of the dead? But if there be no resurrection of the dead, then is Christ not risen: And if Christ be not risen, then is our preaching vain, and your faith is also vain. Yea, and we are found false witnesses of God; because we have testified of God that he raised up Christ: whom he raised not up, if so be that the dead rise not. For if the dead rise not, then is not Christ raised: And if Christ be not raised, your faith is vain; ye are yet in your sins. Then they also which are fallen asleep in Christ are perished. If in this life only we have hope in Christ, we are of all men most miserable. But now is Christ risen from the dead, and become the firstfruits of them that slept. For since by man came death, by man came also the resurrection of the dead. For as in Adam all die, even so in Christ shall all be made alive. But every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming. Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power. For he must reign, till he hath put all enemies under his feet. The last enemy that shall be destroyed is death. For he hath put all things under his feet. But when he saith all things are put under him, it is manifest that he is excepted, which did put all things under him. And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all. 
(1 Corinthians 15:12-28)
Because Satan is altogether evil, he could not foresee the unselfish Love that God has to His creation: 
Howbeit we speak wisdom among them that are perfect: yet not the wisdom of this world, nor of the princes of this world, that come to nought: But we speak the wisdom of God in a mystery, even the hidden wisdom, which God ordained before the world unto our glory: Which none of the princes of this world knew: for had they known it, they would not have crucified the Lord of glory. But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him. But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God. 
(1 Corinthians 2:6-10)
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. For God sent not his Son into the world to condemn the world; but that the world through him might be saved. He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God. And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil. For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved. But he that doeth truth cometh to the light, that his deeds may be made manifest, that they are wrought in God. 
(John 3:16-21)