Nothing Impossible with God
Luke 1:37 (ESV) … “For nothing will be impossible with God.”
Mary did not ask for a sign, but it seems that Gabriel gave her one by explaining that Mary’s relative Elizabeth was also pregnant as the result of God’s grace. Gabriel gave Mary a person to whom she could go for support during what could prove to be a difficult time for Mary as she humbly fulfilled God’s will. This also illustrated for Mary the fact that nothing is impossible with God. God took a barren woman who was past childbearing age and caused her to become pregnant. God took a virgin and caused a child to grow in her womb. With God, nothing is impossible (see 18:27; Genesis 18:14; Jeremiah 32:17, 27; Matthew 17:20; 19:26; Mark 10:27).
 Barton, B. B., Veerman, D., Taylor, L. C., & Osborne, G. R. (1997). Luke (p. 22). Tyndale House Publishers.