We can always be happy, but we need to think more to make it real.
I Thessalonians 5:16 says:
That is an incredible and very short verse.
If we look at Jesus, we can see many emotions like anger, sorrow, and anguish that I would never describe as rejoicing. He also had times where he visibly rejoiced like when the disciples came back after going out two by two.
How can we say that Jesus was rejoicing always?
I Cor 6:10 speaks to this question:
10 sorrowful, yet always rejoicing; poor, yet making many rich; having nothing, and yet possessing everything.
We are children of the great King over all creation. We children of the king may cry when they scrape their knee, but within we have a high positive sense that we are loved, protected and provided for despite the scraped knee we see now.
Furthermore, despite our failings, Jesus will always welcome us home. We have reason to be joyful always. Paul did not just speak nice words to the Thessalonians. He fully meant what he said.
We Can Be Happy Always With Discernment
Jesus was not despondent and without hope in Gethsemane. He had natural human fear of bearing physical death and the wrath of his Father. Passed that, he was a tower of strength that amazed Pilate. Jesus endured horror, but knew he was living and dying for a very good reason. He was not lost as the pagans lose. He knew all of life had meaning, and especially his obedience had meaning to the extreme.
Let’s also talk about Depression. Having experienced depression and lived with people with depression, I know that sharing these words will not help hardly anyone with depression who must read it. They often do best if they find such words themselves.
My goal is not to condemn people who feel they cannot get there. None of us can get there. We all will fall short. However, rejoice always is a gift to those who can receive it. I cannot see Paul dogmatically chasing a person who is not ready to commit to this gift.
The gift of trusting the truth of our relationship still remains. Let us rejoice in such a life given to us. See also Did Jesus Give Us A Free Gift? The gift is not free, it is the invitation to relationship which requires our trust especially in trial. God help us see our life well.