Proverbs 15:8 The sacrifice of the wicked is an abomination to the Lord: but the prayer of the upright is his delight.
This word is not a direct promise, but a promise is embedded in this truth: God promises to be delighted in the prayers of His children. This a wonderful promise for us to believe and think about. The Lord delights in His true believers all the time, and He is especially joyful when we talk to Him. Think about it: as His children we have the ability to bring joy to the Lord and make His heart glad.
Our Father delights in His Son: “You are my beloved Son; with you I am well pleased.” Our Father delights in us, who identify with Christ by faith. Our Father delights in His loving relationship with His children. My Father delights in me. Our Father is filled with joy when we just talk to Him, even if it is just to make a mundane or worldly request. It thrills the heart of God just to hear us pray.
On the negative side, the sacrifice (worship and prayer) of the wicked (the unbeliever) is an abomination to the Lord. The difference is one of faith in Christ or not. Abomination and delight is not differentiated by sincerity or insincerity, nor even on a little faith or a lot of faith, and certainly not by good deeds, but it is solely based in faith or unbelief in Christ. “Without faith it impossible to please God.” With faith God is well pleased, and He delights in you.