Philip Melanchthon was a brilliant scholar (one of the greatest Greek interpreters of his day), an insightful theologian, and Martin Luther’s right-hand man.  He was also one of those easily depressed Danny Downers that you want to shake and cajole and get them out of their funk.  Melancthon was very depressed about the progress of the Reformation to the point he was bed ridden.  Luther wrote him ….

I pray for you very earnestly, and I am deeply pained that you keep sucking up cares like a leech and thus rendering my prayers vain. Christ knows whether it comes from stupidity or the Spirit, but I for my part am not very much troubled about our cause. Indeed, I am more hopeful than I expected to be. God who is able to raise the dead is also able to uphold his cause when it is falling or to raise it up again when it has fallen or to move it forward when it is standing. If we are not worthy instruments to accomplish his purpose, he will find others. If we are not strengthened by his promises, where in all the world are the people to whom these promises apply? But more of this another time. After all, my writing this is like pouring water into the sea.