"Moreover the LORD spake again unto Ahaz, saying, 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 7:10-14