Phil. 4:4 Rejoice in the Lord always; again I will say, rejoice.
1 Thes. 5:16 Always rejoice.
The first thing we have to know is that rejoicing is a commandment of God. The Bible commands us not to be happy, but to rejoice in the Lord. We should not only rejoice in the Lord, but rejoice in Him always. Perhaps you may think, "I have such and such a problem. How can I rejoice? I am a laborer and have to support a family. Even though I toil and sweat, I do not earn much in wages, and living expenses are so high. How can I rejoice?" As a result, you may become anxious. Perhaps you are a student, doctor, master, or servant, and you feel that it is difficult to deal with other people in the world. You cannot rejoice.
Indeed, many things can make you unable to rejoice. But please note that the rejoicing in verse 4 is not to rejoice in yourself, but to "rejoice in the Lord always." God has not asked us to rejoice in our environment, in things going our way, or in any kind of happiness.
The world may oppose us, misunderstand us, reject us, and trap us, but no one can cover the heavens from us. The Lord never changes. We should be clear about one thing: do not rejoice in the environment; rather, rejoice in our Lord. When friends and relatives are away and the heart is aching and weeping, we can be comforted and rejoice if we look to the Lord who loves us and whom we love. He is enough to satisfy our heart. But Christians are very forgetful! We may hear about this today but forget about it tomorrow! This is why Paul followed by saying, "Again I will say, rejoice." God's intention is that we rejoice. Therefore, whatever happens, we must rejoice.
Thank You, Lord Jesus, that my problems cannot stop me from rejoicing. I pray You will help me not to forget that in every situation I can rejoice in You. Also, remind me that this is what You've charged me to do. In Jesus name I pray. Amen.