In this passage, the lord is telling us that we need to line up our desires with His desires, which first we need to understand what "delight ourselves in the Lord" means! it means we need to realize that our heavenly father wants us to literally jump up in his lap and wrap our arms around him and give him a big slobbery kiss on the lips and truly fall in love with him!

By doing so we will think more like he thinks and do more like he would have us to do. our delightment becomes His will and our desires become his desires, the desires our heart will all come to pass in his perfect time...