How did Christ, being the Son of God, become man?

Christ, the Son of God, became man, by taking to himself a true body, and a reasonable soul, being conceived by the power of the Holy Ghost, in the womb of the Virgin Mary, and born of her yet without sin.

Hebrews 2:14 (ESV)
Since therefore the children share in flesh and blood, he himself likewise partook of the same.

Matthew 26:38 (ESV)
Then he said to them, “My soul is very sorrowful, even to death; remain here, and watch with me.”

Luke 1:31 (ESV)
And behold, you will conceive in your womb and bear a son, and you shall call his name Jesus.

Luke 1:35 (ESV)
And the angel answered her, “The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the child to be born will be called holy—the Son of God.

Hebrews 7:26 (ESV)
For it was indeed fitting that we should have such a high priest, holy, innocent, unstained, separated from sinners, and exalted above the heavens.