God says... "Yes but..." (Gen 17)

Abraham fell facedown; he laughed and said to himself, "Will a son be born to a man a hundred years old? Will Sarah bear a child at the age of ninety?" 18 And Abraham said to God, "If only Ishmael might live under your blessing!" Then God said, "Yes, but....

God still answers our inquiries this way.  

me:  I thought you were going to provide for my needs.

HIM: Yes, but I have something to teach you.

me: Didn't you say that you'll answer my prayers?

HIM: Yes, but if you'll just wait on me I'll answer questions that are more important than the your finite requests.

me: Can I really know You more, deeper, with more certainty?

HIM: Yes, but it's going to require everything you have.