Trust in the Lord and do good; dwell in the land and enjoy safe pasture. Take delight in the Lord, and he will give you the desires of your heart.
“The reason many apparent Christians do not delight in God is that they do not know him very well, and the reason they do not know him very well is that they do not spend time with him.” (Boice)
This is one of my favorite psalms? Why? We delight in a lot of things in this life, but we might think it strange to delight in the Lord? As the commentary by Boice says, "We probably don't delight in the Lord because we don't know Him. And we don't know him because we don't spend time with him."
To be fair the idea of delighting in someone you can't see is daunting. But that is why God has revealed himself to us. He has revealed Himself to us generally through His Creation. When we look at the sun, moon and the stars, or a beautiful sunset; we see how beautiful and artistic God is. We can delight in who He is as we reflect on the beauty of what He has made.
Second, God revealed specifically who He is when He sent Jesus to the earth. Jesus said, "If you have seen me you have seen the Father." (John 14:9) Jesus came to earth to show us the Way to the Father. Jesus spent long periods His Heavenly Father before he did anything. The hardest part of being on the cross for Jesus was when he felt a break in His relationship with His Father and said, "My God, my God why have you forsaken me?"
Finally, this psalm makes a promise. If you delight yourself in God, He will give you the desires of your heart. God wants to you feel the sense of your desires being met. He wants us to be happy. God gave you those desires. As you delight in Him, He will meet your innermost needs, especially your need to know and be known by Him!
What do you desire most in your life? Is God the list? Delight yourself in the Lord and He will give you the desires of your heart! This leads to true happiness in the best sense of the word.