Martin Luther, writing to Prince Joachim:
Gladness and good cheer, when decent and proper, are the best medicine for a young person – indeed, for all people.
I myself, who have spent a good part of my life in sorrow and gloom, now seek and find pleasure wherever I can. Praise God, we now have sufficient understanding [of the Word of God] to be able to rejoice with a good conscience and to use God’s gifts with thanksgiving, for he created them for this purpose and is pleased when we use them…
It is my opinion that [you are] reluctant to be merry, as if this were sinful. This has often been my case, and sometimes still is. To be sure, to have pleasure in sins is of the devil, but participation in proper and honorable pleasures with good and God-fearing people is pleasing to God, even if one may at times carry playfulness too far.
Be merry, then, both inwardly in Christ himself and outwardly in his gifts and the good things of his life. He will have it so. It is for this that he is with us. It is for this that he provides his gifts – that we may use them and be glad, and that we may praise, love, and thank him forever and ever (Luther: Letters of Spiritual Comfort, 93).
We are to count everything as loss because of the surpassing worth of knowing Christ (Phil 3:8), yet we are also to receive everything God created with thankfulness (1 Tim. 4:4). For a large part of my life, I wanted Christ’s gifts without Christ. For another portion of my life, I thought that to find my joy in Christ meant that joy in other things was illegitimate. Luther sanely holds the tension together.