Isaiah 37:30

And he said, Certainly I will be with thee; and this shall be a token unto thee, that I have sent thee: When thou hast brought forth the people out of Egypt, ye shall serve God upon this mountain.

And he gave a sign the same day, saying, This is the sign which the LORD hath spoken; Behold, the altar shall be rent, and the ashes that are upon it shall be poured out. And it came to pass, when king Jeroboam heard the saying of the man of God, which had cried against the altar in Bethel, that he put forth his hand from the altar, saying, Lay hold on him. And his hand, which he put forth against him, dried up, so that he could not pull it in again to him. The altar also was rent, and the ashes poured out from the altar, according to the sign which the man of God had given by the word of the LORD.

And this shall be a sign unto thee, Ye shall eat this year such things as grow of themselves, and in the second year that which springeth of the same; and in the third year sow ye, and reap, and plant vineyards, and eat the fruits thereof.

And Isaiah said, This sign shalt thou have of the LORD, that the LORD will do the thing that he hath spoken: shall the shadow go forward ten degrees, or go back ten degrees?

Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.

And this shall be a sign unto thee from the LORD, that the LORD will do this thing that he hath spoken;