...in every situation, by prayer and petition, with thanksgiving, present your requests to God.(Philipians 4:6b)Thanksgiving is a manifestation of faith and a necessary part of it. In the verse above, notice that we are to present our request to God with thanksgiving. In other words, we are to be thankful as we present them to God; not after they have been granted. We are so to trust God's will that we can expect our prayers to be answered in the way He knows is best. They may not be answered in the way we initially desire, hope, or even expect, but we can pray in thankful expectation that His will is good and pleasing and perfect (Romans 12:2b)
Faith is not presumptiously believing that God will answer each of our demands according to our own narrow will. It is trusting that He will conform our desires to His, and that our prayers will be answered according to His will. It is the confidence that His will is so much bigger and better than ours.