Too Wonderful or Too Impossible for God?

As I read the Hebrew Scripture selection from the lectionary for Sunday (Genesis 18:1-15 as portrayed in Rublev's icon) I was stopped by v. 14 "Is anything too wonderful for God?" and prompted to look up the parallel in Luke 1:37 "For nothing will be impossible with God." As our transition from Dallas to Milwaukee has taken a number of unexpected turns, at each of which God's whispers have been coaxing us along the path, Candy's Dad's fall, broken hip, surgery, and rehab are the current uncertainty, I am encouraged to trust God in another surprise in which we don't know where the path will lead. I am also drawn again to Thomas Merton's prayer.

My Lord God,
I have no idea where I am going.
I do not see the road ahead of me.
I cannot know for certain where it will end.
Nor do I really know myself,
And the fact that I think I am following your will does not mean that I am actually doing so.
But I believe that the desire to please you does in fact please you.
And I hope I have that desire in all that I am doing.
I hope that I will never do anything apart from that desire.
And I know that if I do this, you will lead me by the right road
Though I may know nothing about it.
Therefore I will trust you always
Though I may seem to be lost
And in the shadow of death.
I will not fear, for you are ever with me,
And you will never leave me to face my perils alone.

Thomas Merton in Thoughts in Solitude, page 83

Then I come to this in my daily Psalm prayers from Psalm 43:3. "Send out your light and your truth; let them lead me."