I Thessalonians 5:16-18: Be joyful always; pray continually; give thanks in all circumstances, for this is God's will for you in Christ Jesus.
Philippians 4: 4-7: Rejoice in the Lord always. I will say it again: Rejoice! Let your gentleness be evident to all. The Lord is near. Do not be anxious about anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus.
Ephesians 5: 19-20: Speak to one another with psalms, hymns and spiritual songs. Sing and make music in your heart to the Lord, always giving thanks to God the Father for everything, in the name of our Lord Jesus Christ.