Romans 5:11
And not only is this true, but we also rejoice in God, through our Lord Jesus Christ, through whom we have been restored to fellowship with God.
Philippians 3:1
Finally, my brothers, rejoice in [your relationship to] the Lord. It does not trouble me to write the same things to you again, because you will be safer if I do. [Note: These "same things" may refer to warnings against false teachers which Paul had either spoken to them or written about previously].
Philippians 3:3
For we [Christians] are the [true] circumcision [i.e., the real "Jews" in God's eyes. See Rom. 2:28-29]. We worship by means of God's Holy Spirit [i.e., are empowered and motivated by the Holy Spirit], and boast in [the person and work of] Christ Jesus, and [we] place no confidence in the flesh [i.e., in any outward ritual or status for salvation].
Philippians 4:4
Rejoice in [fellowship with] the Lord all the time. I will say it again: Rejoice!