The only Begotten Son enters Mary to be born as all babies are born. God reduced himself to a one-cell fertilized ovum inside Mary’s body! What humility! Once this union takes place, before the first division of the cell, “It” is not half-human and “It” is not half-divine. Fully God and fully man. The first step of incarnation! What mystery! What redemption! Incarnation expresses the loving intention of God for union with us.
“The angel answered and said to her, “The Holy Spirit will come upon you, and the power of the Most High will overshadow you; and for that reason the holy Child shall be called the Son of God” Luke 1:35 (NASB).