For the rest, my brethren, delight yourselves in the Lord and continue to rejoice that you are in Him. To keep writing to you [over and over] of the same things is not irksome to me, and it is [a precaution] for your safety. Philippians 3:1 (AMPC)
Delighting yourself in the Lord is a result of knowing who you’re in Him and what you have in Him.
When you know that in Him you’re everlastingly loved as a son or daughter it will bring you delight. When you know that you are unconditionally accepted in Him you will rejoice. When you know that in Him you have forgiveness of all sins through His Blood the result is joy unspeakable.
The knowledge, the conviction, the consciousness that the Lord is your Shepherd therefore you lack nothing is an ever flowing stream of unceasing delight. You will laugh triumphantly in the face of trouble when you know that you’re more than a conqueror in Him who loved you.