The world we live in is not the world God created it to be. So, it's easy for us to look at our circumstances and believe that while God can save us spiritually, in some vague sense, we cannot trust him with the specifics or our day-to-day lives. The Incarnation, however, teaches us that God fulfills his promises methodically and specifically. He entered into our fleshly world, concerned himself with our fleshly worries, and redeemed our fleshly lives. In Luke 1:55, Mary's song of praise exemplifies this truth: God's promises may not be fulfilled immediately or in the manner we expect, but He will fulfill them at the perfect time and in a perfect way.
Luke 1:46-55 English Standard Version (ESV)
Mary's Song of Praise: The Magnificant
46 And Mary said, “My soul magnifies the Lord, 47 and my spirit rejoices in God my Savior, 48 for he has looked on the humble estate of his servant. For behold, from now on all generations will call me blessed; 49 for he who is mighty has done great things for me, and holy is his name. 50 And his mercy is for those who fear him from generation to generation. 51 He has shown strength with his arm; he has scattered the proud in the thoughts of their hearts; 52 he has brought down the mighty from their thrones and exalted those of humble estate; 53 he has filled the hungry with good things, and the rich he has sent away empty. 54 He has helped his servant Israel, in remembrance of his mercy, 55 as he spoke to our fathers, to Abraham and to his offspring forever.”