Charles H. Spurgeon on Psalms 25:18

Look upon mine affliction and my pain; and forgive all my sins. We may observe here, that sickness and weakness of the body come from sin, and is a fruit of sin. Some are weak, and some are sick, "for this cause." I shall not need to be long in the proof of that, which you have whole chapters for, as De 28:27, seq; and many Psalms, 107, and others. It is for the sickness of the soul that God visits with the sickness of the body. He aims at the cure of the soul in the touch of the body. And therefore in this case, when God visits with sickness, we should think our work is more in heaven with God than with men or physic. Begin first with the soul. So David Ps 32:5, till he dealt roundly with God, without all kind of guile, and confessed his sins, he roared; his moisture was turned into the drought of summer. But when he dealt directly and plainly with God, and confessed his sins, then God forgave him them, and healed his body too. And therefore the best method, when God visits us in this kind, is to think that we are to deal with God. Begin the cure there with the soul. When he visits the body, it is for the soul's sake: "Many are weak and sickly among you." Richard Sibbes.