Isaiah 7:14 can only mean a virgin. If it was merely referring to a “young maiden,” as some maintain, it would not have been a miraculous “sign” from God. Every day, thousands of young maidens conceive; only once has it happened to a virgin. This messianic prophecy was fulfilled in Luke 1:31–35; Matt. 1:18–23.
Isaiah 7:14 Therefore the Lord Himself will give you a sign: Behold, the virgin shall conceive and bear a Son, and shall call His name Immanuel.