Delight thyself also in the LORD; and he shall give thee the desires of thine heart. (Psalm 37:4 KJV)This is not the prosperity gospel. This isn't saying "follow God (or suck up to God) and you'll get everything you want." It's saying if the "desires of thine heart" are to find delight in the Lord, then you will get those desires.
This isn't about delighting in God in order to get something else. It's about allowing yourself to delight in God, truly wanting to delight in God, and knowing that you will have that delight.
God answers every prayer with a "yes" or a "no," but the one prayer he will always answer with a solid, undeniable "yes" is your sincere prayer to delight in him. God may not give you a pony or a plastic rocket, but he will always give you himself if he is what you truly delight in and desire.