This Shall be a Sign unto You 
The Jews, as described in the Bible, usually expected a spiritual sign as confirmation of the truth of the words of a prophet or other spiritual being. 
This expectation went back at least to the days of Moses and was documented by him in the Pentateuch - the first five books of the Bible. 
And Moses answered and said, But, behold, they will not believe me, nor hearken unto my voice: for they will say, The LORD hath not appeared unto thee. And the LORD said unto him, What is that in thine hand? And he said, A rod. And he said, Cast it on the ground. And he cast it on the ground, and it became a serpent; and Moses fled from before it. And the LORD said unto Moses, Put forth thine hand, and take it by the tail. And he put forth his hand, and caught it, and it became a rod in his hand: That they may believe that the LORD God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath appeared unto thee. And the LORD said furthermore unto him, Put now thine hand into thy bosom. And he put his hand into his bosom: and when he took it out, behold, his hand was leprous as snow. And he said, Put thine hand into thy bosom again. And he put his hand into his bosom again; and plucked it out of his bosom, and, behold, it was turned again as his other flesh. And it shall come to pass, if they will not believe thee, neither hearken to the voice of the first sign, that they will believe the voice of the latter sign. And it shall come to pass, if they will not believe also these two signs, neither hearken unto thy voice, that thou shalt take of the water of the river, and pour it upon the dry land: and the water which thou takest out of the river shall become blood upon the dry land
(Exodus 4:1-9)
Speak thou also unto the children of Israel, saying, Verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the LORD that doth sanctify you. Ye shall keep the sabbath therefore; for it is holy unto you: every one that defileth it shall surely be put to death: for whosoever doeth any work therein, that soul shall be cut off from among his people. Six days may work be done; but in the seventh is the sabbath of rest, holy to the LORD: whosoever doeth any work in the sabbath day, he shall surely be put to death. Wherefore the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations, for a perpetual covenant. It is a sign between me and the children of Israel for ever: for in six days the LORD made heaven and earth, and on the seventh day he rested, and was refreshed. And he gave unto Moses, when he had made an end of communing with him upon mount Sinai, two tables of testimony, tables of stone, written with the finger of God. 
(Exodus 31:13-18)
Also in many other places in the Old Covenant:
Ask thee a sign of the LORD thy God; ask it either in the depth, or in the height above. But Ahaz said, I will not ask, neither will I tempt the LORD. And he said, Hear ye now, O house of David; Is it a small thing for you to weary men, but will ye weary my God also? Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel. 
(Isaiah 7:11-14)
Then Isaiah the son of Amoz sent unto Hezekiah, saying, Thus saith the LORD God of Israel, Whereas thou hast prayed to me against Sennacherib king of Assyria: This is the word which the LORD hath spoken concerning him; The virgin, the daughter of Zion, hath despised thee, and laughed thee to scorn; the daughter of Jerusalem hath shaken her head at thee. Whom hast thou reproached and blasphemed? and against whom hast thou exalted thy voice, and lifted up thine eyes on high? even against the Holy One of Israel. By thy servants hast thou reproached the Lord, and hast said, By the multitude of my chariots am I come up to the height of the mountains, to the sides of Lebanon; and I will cut down the tall cedars thereof, and the choice fir trees thereof: and I will enter into the height of his border, and the forest of his Carmel. I have digged, and drunk water; and with the sole of my feet have I dried up all the rivers of the besieged places. Hast thou not heard long ago, how I have done it; and of ancient times, that I have formed it? now have I brought it to pass, that thou shouldest be to lay waste defenced cities into ruinous heaps. Therefore their inhabitants were of small power, they were dismayed and confounded: they were as the grass of the field, and as the green herb, as the grass on the housetops, and as corn blasted before it be grown up. But I know thy abode, and thy going out, and thy coming in, and thy rage against me. Because thy rage against me, and thy tumult, is come up into mine ears, therefore will I put my hook in thy nose, and my bridle in thy lips, and I will turn thee back by the way by which thou camest. And this shall be a sign unto thee, Ye shall eat this year such as groweth of itself; and the second year that which springeth of the same: and in the third year sow ye, and reap, and plant vineyards, and eat the fruit thereof. And the remnant that is escaped of the house of Judah shall again take root downward, and bear fruit upward: For out of Jerusalem shall go forth a remnant, and they that escape out of mount Zion: the zeal of the LORD of hosts shall do this. Therefore thus saith the LORD concerning the king of Assyria, He shall not come into this city, nor shoot an arrow there, nor come before it with shields, nor cast a bank against it. By the way that he came, by the same shall he return, and shall not come into this city, saith the LORD. For I will defend this city to save it for mine own sake, and for my servant David's sake. Then the angel of the LORD went forth, and smote in the camp of the Assyrians a hundred and fourscore and five thousand: and when they arose early in the morning, behold, they were all dead corpses. 
(Isaiah 37:21-36)
An example, as described in the previous teaching1 on this web site2 
And she brought forth her firstborn son, and wrapped him in swaddling clothes, and laid him in a manger; because there was no room for them in the inn. And there were in the same country shepherds abiding in the field, keeping watch over their flock by night. And, lo, the angel of the Lord came upon them, and the glory of the Lord shone round about them: and they were sore afraid. And the angel said unto them, Fear not: for, behold, I bring you good tidings of great joy, which shall be to all people. For unto you is born this day in the city of David a Saviour, which is Christ the Lord. And this shall be a sign unto you; Ye shall find the babe wrapped in swaddling clothes, lying in a manger. And suddenly there was with the angel a multitude of the heavenly host praising God, and saying, Glory to God in the highest, and on earth peace, good will toward men. And it came to pass, as the angels were gone away from them into heaven, the shepherds said one to another, Let us now go even unto Bethlehem, and see this thing which is come to pass, which the Lord hath made known unto us. And they came with haste, and found Mary, and Joseph, and the babe lying in a manger. 
(Luke 2:7-16) 
In the days of the public ministry of Jesus of Nazareth, the Pharisees and other leaders wanted a sign above the signs given them by the prophets concerning the timing etc.of the coming of the Messiah. Even the common people knew of these prophecies, yet the leaders demanded another sign from Jesus, which He gave them and which they failed to acknowledge: 
Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee. But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas: For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth. The men of Nineveh shall rise in judgment with this generation, and shall condemn it: because they repented at the preaching of Jonas; and, behold, a greater than Jonas is here. The queen of the south shall rise up in the judgment with this generation, and shall condemn it: for she came from the uttermost parts of the earth to hear the wisdom of Solomon; and, behold, a greater than Solomon is here. When the unclean spirit is gone out of a man, he walketh through dry places, seeking rest, and findeth none. Then he saith, I will return into my house from whence I came out; and when he is come, he findeth it empty, swept, and garnished. Then goeth he, and taketh with himself seven other spirits more wicked than himself, and they enter in and dwell there: and the last state of that man is worse than the first. Even so shall it be also unto this wicked generation. 
(Matthew 12:38-45)
hence the persecution of the believers by the Jews as described in the book of Acts: 
And by the hands of the apostles were many signs and wonders wrought among the people; (and they were all with one accord in Solomon's porch. And of the rest durst no man join himself to them: but the people magnified them. And believers were the more added to the Lord, multitudes both of men and women.) Insomuch that they brought forth the sick into the streets, and laid them on beds and couches, that at the least the shadow of Peter passing by might overshadow some of them. There came also a multitude out of the cities round about unto Jerusalem, bringing sick folks, and them which were vexed with unclean spirits: and they were healed every one. Then the high priest rose up, and all they that were with him, (which is the sect of the Sadducees,)and were filled with indignation, And laid their hands on the apostles, and put them in the common prison. But the angel of the Lord by night opened the prison doors, and brought them forth, and said, Go, stand and speak in the temple to the people all the words of this life. And when they heard that, they entered into the temple early in the morning, and taught. But the high priest came, and they that were with him, and called the council together, and all the senate of the children of Israel, and sent to the prison to have them brought. But when the officers came, and found them not in the prison, they returned, and told, Saying, The prison truly found we shut with all safety, and the keepers standing without before the doors: but when we had opened, we found no man within. Now when the high priest and the captain of the temple and the chief priests heard these things, they doubted of them whereunto this would grow. Then came one and told them, saying, Behold, the men whom ye put in prison are standing in the temple, and teaching the people. Then went the captain with the officers, and brought them without violence: for they feared the people, lest they should have been stoned. And when they had brought them, they set them before the council: and the high priest asked them, Saying, Did not we straitly command you that ye should not teach in this name? and, behold, ye have filled Jerusalem with your doctrine, and intend to bring this man's blood upon us. Then Peter and the other apostles answered and said, We ought to obey God rather than men. The God of our fathers raised up Jesus, whom ye slew and hanged on a tree. Him hath God exalted with his right hand to be a Prince and a Saviour, for to give repentance to Israel, and forgiveness of sins. And we are his witnesses of these things; and so is also the Holy Ghost, whom God hath given to them that obey him. When they heard that, they were cut to the heart, and took counsel to slay them. 
(Acts 5:12-33)
We also see that Jesus told us always to expect spiritual signs in our lives, for God's glory: 
He that hath my commandments, and keepeth them, he it is that loveth me: and he that loveth me shall be loved of my Father, and I will love him, and will manifest myself to him. 
(John 14:21)
Afterward he appeared unto the eleven as they sat at meat, and upbraided them with their unbelief and hardness of heart, because they believed not them which had seen him after he was risen. And he said unto them, Go ye into all the world, and preach the gospel to every creature. He that believeth and is baptised shall be saved; but he that believeth not shall be damned. And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover. So then after the Lord had spoken unto them, he was received up into heaven, and sat on the right hand of God. And they went forth, and preached every where, the Lord working with them, and confirming the word with signs following. Amen. 
(Mark 16:14-20)
The Christians of the early Church experienced many signs: 
And when they were escaped, then they knew that the island was called Melita. And the barbarous people shewed us no little kindness: for they kindled a fire, and received us every one, because of the present rain, and because of the cold. And when Paul had gathered a bundle of sticks, and laid them on the fire, there came a viper out of the heat, and fastened on his hand. And when the barbarians saw the venomous beast hang on his hand, they said among themselves, No doubt this man is a murderer, whom, though he hath escaped the sea, yet vengeance suffereth not to live. And he shook off the beast into the fire, and felt no harm. Howbeit they looked when he should have swollen, or fallen down dead suddenly: but after they had looked a great while, and saw no harm come to him, they changed their minds, and said that he was a god. In the same quarters were possessions of the chief man of the island, whose name was Publius; who received us, and lodged us three days courteously. And it came to pass, that the father of Publius lay sick of a fever and of a bloody flux: to whom Paul entered in, and prayed, and laid his hands on him, and healed him. 
(Acts 28:1-8)
Many "christians" today say that there are no signs anymore, that this was only up to the first century AD or so. 
Do you believe this?
Have you perhaps studied the previous writing1 on the web site, or the one entitled "The Mouse That Thundered"? 
Do you experience God's providence and other supernatural occurrences in your life on a regular basis? 
God has promised this to the sheep of His pasture. 
And whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight. And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment. And he that keepeth his commandments dwelleth in him, and he in him. And hereby we know that he abideth in us, by the Spirit which he hath given us. 
(1 John 3:22-24) 
1 Watch.