How do we know that Jesus was born of a virgin?

The virgin birth of Jesus is crucial for understanding His nature as the sinless Son of God. Isaiah 7:14 clearly prophesizes that a virgin shall conceive and bear a son, thus highlighting the miraculous nature of Christ's entrance into the world. This necessity stems from the theological understanding that Jesus needed to be without sin to be an adequate substitute for sinners, as He was not born of the seed of man, and therefore, had no original sin in Him. In fulfilling this prophecy, He was not just a man but the God-man, uniquely qualified to redeem His people through His life, death, and resurrection.