The Lord spoke to King Ahaz that he asked for a sign, whether on the Earth or in heaven,

But Ahaz said, “I will not ask, nor will I test the Lord!” Then he said, “Hear now, O house of David! Is it a small thing for you to weary men, but will you weary my God also? Therefore the Lord Himself will give you a sign: Behold, the virgin shall conceive and bear a Son, and shall call His name Immanuel” (Isaiah 7.12–14).

The house of David thought that since it could weary men, it could weary the Lord, but He would show them the wonderful things He could do, causing a virgin to conceive and to bear a Son.

Only the true God of heaven above could do such a thing, and when Jesus of Nazareth entered the world, He fulfilled this magnificent passage.