Psalm 37:4 states succinctly "Delight thyself also in the Lord; and he shall give thee the desires of thine heart" (KJV).
A close examination reveals this is an injunction (order and command) as well as a piece of advice (counsel and recommendation) with attendant rewards: He shall give you the desires of your heart!
What does it mean to delight? Simply put, it means to please greatly. We were created for God's pleasure.
"Thou art worthy, O Lord, to receive glory and honour and power: for thou hast created all things, and for thy pleasure they are and were created."
Revelations 4:11 (KJV)
As you delight in Our Father in Heaven, not just mere wants and needs, but the very bests of your good heart's desires will be granted and given to you on a platter of gold.
Merry delighting in the Lord!