"Always be rejoicing."
with these words the apostle Paul encouraged the Christian congregation.
(1 Thessalonians 5:16; compare: 2 Corinthians 13:11)
Rejoice means to feel and express joy. It does not mean to be in a constant state of exuberance.
Is it possible to always be rejoicing?
Yes, because true joy is a quality of heart, a deep inner quality, a spiritual quality.
"A joyful heart has a good effect on the countenance..."
Joy is a fruit of God's spirit, listed right after love.
This quality is not dependent on external things. However, it does depend on God's holy spirit.
Joy is not a personality trait we are born with, it is a quality that distinquished Jesus and that we can cultivate and put on. We are encouraged by these words: "clothe yourselves with the new personality, which through accurate knowledge is being made new according to the image of the One who created it." -Colossians 3:10. Yes! Joy can become part of our personality as we imitate Jesus example and pray for God's holy spirit to be active in our lives.
True Joy comes from the deep inner satisfaction of knowing we are doing what pleases our heavenly Father.
It must be remembered that being a servant of God does not free us from experiencing family problems, economic difficulties, health issues, or the death of loved ones. These things cause us sorrow, but do not take away our basis for rejoicing in the Kingdom hope, the inner joy that we have in our heart. During times of sorrow we can "rejoice in the hope." which will help us, "endure under tribulation". (Romans 12:12)
We can hope in the fulfillment of the prophecies of Isaiah, apostle Peter and the apostle John:
"For here I am creating new heavens and a new earth; and the former things will not come to mind, neither will they come up into the heart. But exult you people, and be joyful forever in what I am creating..."-Isaiah 65:17, 18
"But there are a new heavens, and a new earth that we are awaiting according to his promise, and in theses righteousness is to dwell." -2 Peter 3:13
"And I saw a new heaven and a new earth; for the former heaven and the former earth had passed away...Look! The tent of God is with mankind, and he will reside with them, and they will be his peoples. And God himself will be with them. And he will wipe out every tear from their eyes, and death will be no more, neither will mourning nor outcry nor pain be anymore. The former things have passed away. And the One seated on the throne said: 'Look! I am making all things new.' Also, he says: 'Write, because these words are faithful and true.'" -Revelation 21:1-5
Yes, it is Joy that helps us endure while under tribulation. We can rejoice in this hope, knowing that the promise of a peaceful new heavens (heavenly kingdom government) and new earth (righteous subjects of God's kingdom) will be our reward to time indefinite! For all God's joyful servants this new heavens and new earth will guarantee a true peace.