The devotion below is from Experiencing God Daily / Blackaby Ministries - http://www.blackaby.org/ ; there is great truth in this devotion. Many of us tend to let our circumstances or other people rob us of our joy. We can choose to not let this happen, and choose instead to rejoice in the Lord - at all times.
But at midnight Paul and Silas were praying and singing hymns to God, and the prisoners were listening to them. (Acts 16:25)
Your joy as a Christian should not depend on your circumstances. Joy comes from God, and therefore it cannot be affected by what is outside of you. Don’t be fooled into letting the actions of others determine your joy. True joy comes from knowing that God Himself lives within you and has fellowship with you, regardless of your environment. Real joy lies in the knowledge that holy God has completely forgiven you of every sin, and even now, He has a home prepared in heaven where you can spend eternity with Him (John 14:3). The circumstances of your life cannot change these truths!
Paul and Silas faced some of the most difficult circumstances imaginable. They were falsely accused, arrested, and imprisoned. They were beaten and shackled in the darkest, coldest section of the prison. But they refused to allow their horrific situation to dampen their joy! They did not blame God for allowing these things to happen to them. Instead, they praised Him for His goodness! In the darkness of the night, they prayed and they sang. God brought a miracle that released them from their chains, but perhaps the greater miracle was that His Holy Spirit could so fill them that even in their painful imprisonment they could overflow with joy!
Do not allow difficult events to cancel the joy of knowing you are a child of God. Choose to allow God’s Spirit to fill you with His unquenchable joy, and your life will be a miracle to those who watch you face the trials that come.