Paradox

"Let me illustrate some the paradoxes of the Christian life by simply quoting the apostle Paul. He described his own life in 2 Corinthians 6:8-10 like this:

... as sorrowful, yet always rejoicing; as poor, yet making many rich; as having nothing, and yet possessing everything.

This is what I mean by the paradoxes of the Christian life. Paul says he is "sorrowful, yet always rejoicing." How can you be always rejoicing if you are sometimes sorrowful? There must be some kind of "sorrowful joy" and "joyful sorrow." Indeed, there is—that is one of the deep paradoxes of life for those who rest in a sovereign God and live in a sinful world." - John Piper, Urgency and Gratitude

"There is no unadulterated joy in this world for people who care about others. The Bible describes Christ’s servants like this: “[We are] sorrowful, yet always rejoicing.” (2 Corinthians 6:10).

“Sorrowful yet always rejoicing.” How can that be? It can be because Christ is supreme over all things forever, but suffering and death remain for a while. Life is not simple. There is pleasure, and there is pain. There is sweetness, and there is bitter suffering. There is joy, and there is misery. There is life and health, and there is disease and death. And therefore emotions are not simple. For those who love others, and not just their own comforts, this complexity means that we will rejoice with those who rejoice and weep with those who weep (Romans 12:15). And there is always someone we know who is weeping, and someone we know who is rejoicing. And therefore we will learn the secret of “sorrowful yet always rejoicing”—and joyful yet always sorrowing. Those amazing words that describe the Christian soul—“sorrowful yet always rejoicing”—mean that suffering remains for a while in this world, but Christ is supreme now and forever." - John Piper, The Supremacy of Christ in an Age of Terror

"May God grant us the grace to know and experience what Paul described as his own life in 2 Corinthians 6:10, "sorrowful yet always rejoicing."" - John Piper, Sweet Sorrow: The Root of Holy Living