Rejoice in the Lord always. I will say it again: Rejoice!—Philippians 4:4 (NIV)
The Apostle Paul is saying that our joy should not depend on our external circumstances, which can change and be unpredictable, but rather on our relationship with God, which is unchanging and constant. We should approach problems with a positive and joyful attitude rooted in our faith in God. When we do this, we can experience the peace and comfort that comes from knowing God is with us and in control.
Lord, help me be joyful in all circumstances, focusing on You and trusting in Your righteousness.