Final answer:
The Annunciation is the biblical foundation for the theology of the Incarnation in Mary's life.
Step-by-step explanation:
The biblical foundation for the theology of the Incarnation in the life of Mary is the Annunciation. In this event, the archangel Gabriel announces to Mary that she will conceive the Son of God, Jesus, through the Holy Spirit. This event is recorded in Luke 1:26-38 and is commemorated on March 25.