Ps 104:34, Mt 6:33, 1 Pt 1:8
The Old Testament tells us to rejoice in God. (Psalms 37:4, Psalms 104:34)
Psalms 37:4 Delight thyself also in the Lord: and he shall give thee the desires of thine heart.
Psalms 104:34 My meditation of him shall be sweet: I will be glad in the Lord.
We must first seek the kingdom of God and His righteousness. (Mt 6:33)
Mt 6:33 But seek ye first the kingdom of God, and his righteousness; and all these things shall be added unto you.
We are to love and rejoice in Jesus, the Christ. (1 Peter 1:8)
1 Peter 1:8 Whom having not seen, ye love; in whom, though now ye see him not, yet believing, ye rejoice with joy unspeakable and full of glory: