The angel answered her, "The Holy Spirit will come on you, and the power of the Most High will overshadow you. Therefore also the holy one who is born from you will be called the Son of God.
God settled upon the tabernacle in the wilderness similarly, filling it with His presence (Exodus 40:35; cf. Psalms 91:4). It is interesting that the same Greek word, episkiazo, translated "overshadow" here, occurs in all three accounts of the Transfiguration where the cloud overshadowed those present (Matthew 17:5; Mark 9:7; Luke 9:34). Then the voice came out of heaven identifying God’s Son, but here an angel identified Him as such. The Holy Spirit would produce a holy offspring through Mary. The deity and preexistence of the Son of God required a miraculous conception. His virgin birth resulted in His assuming a human nature without giving up His divine nature.