Jehovah God and Jesus Christ. Jehovah is called “the happy God.” (1Ti 1:11) He creates and works with joy for himself and his creatures. What he brings about makes him joyful. (Ps 104:31) He wants his creatures likewise to enjoy his works and to enjoy their own work. (Ec 5:19) Since he is the Source of all good things (Jas 1:17), all intelligent creatures, both mankind and angels, can find their chief enjoyment in coming to know him. (Jer 9:23, 24) King David said: “Let my musing about him be pleasurable. I, for my part, shall rejoice in Jehovah.” (Ps 104:34) He also sang: “The righteous one will rejoice in Jehovah and will indeed take refuge in him; and all the upright in heart will boast.” (Ps 64:10) The apostle Paul urged Christians to take joy at all times in their knowledge of Jehovah and his dealing with them, writing to them: “Always rejoice in the Lord [“Jehovah,” in several versions]. Once more I will say, Rejoice!”​—Php 4:4.

What makes God joyful. Jehovah’s heart can be made glad by his servants because of their faithfulness and loyalty to him. Satan the Devil has constantly challenged the rightfulness of God’s sovereignty and the integrity of all those serving God. (Job 1:9-11; 2:4, 5; Re 12:10) To them apply the words: “Be wise, my son, and make my heart rejoice, that I may make a reply to him that is taunting me.” (Pr 27:11) Jehovah’s people in the earth can cause God to rejoice by faithfulness and loyalty to him.​—Isa 65:19; Zep 3:17.