Be joyful always; pray continually; give thanks in all circumstances, for this is God's will for you in Christ Jesus.
-- 1 Thessalonians 5:16-18
Always rejoice, always pray, always give thanks. No ifs, ands, or buts.
The key lay in the last verse, which tells us that this is God's will for us in Christ Jesus. In Christ all things are possible.
If we treasure Christ above all, we will be able to rejoice always, pray continually, and give thanks in everything, because Christ alone is the fountain of joy, intimacy with God, and gratitude.
Thanks be to God for his indescribable gift!