Three questions about discipline:
(1) Is all suffering discipline for sin? Or is some not for sin?
Certainly, the Savior suffered, and he never sinned. Moreover, Peter distinguishes between categories of suffering: “This is a gracious thing, when, mindful of God, one endures sorrows while suffering unjustly. For what credit is it if, when you sin and are beaten for it, you endure?” (1 Peter 2:19-20; see also 4:14-15). So, there is much suffering which is not a direct result of one’s own sin.
(2) When we are disciplined for sin, is it for specific sin?
It certainly can be for specific sin. Paul indicts the Corinthians for not examining themselves and repenting, since they have taken the Lord’s supper in an unworthy manner (e.g., rushing, without waiting for each other). Then he says, “That is why many of you are weak and ill, and some have died” (1 Corinthians 11:30). So the Lord’s discipline certainly can be for specific sin.
That conclusion, though, begs the question: Is the Lord’s discipline punitive (i.e., repayment for sin)?
No, for Paul continues, “… when we are judged by the Lord, we are disciplined so that we may not be condemned along with the world” (1 Corinthians 11:32). And as John says, “There is no fear in love, but perfect love casts out fear. For fear has to do with punishment” (1 John 4:18). The true believer receives discipline for his or her good, for correction or salvation, not as punishment. Christ received the repayment of God’s wrath for all the sin we ever commit.
(3) Can discipline for sin not be for specific sin (i.e., for just being a sinner in general)?
After forty years in the wilderness, Moses says to the Israelites that God has been testing and humbling them, letting them hunger and then feeding them manna—all in order for them to know that he alone is Provider. Then he says, “Know then in your heart that, as a man disciplines his son, the LORD your God disciplines you” (Deuteronomy 8:5). The implication then is that the Israelites (not to mention ourselves) needed the trials God brought in order to purge general unbelief from them.
The Proverbs speak similarly: “Blows that wound cleanse away evil; strokes make clean the innermost parts” (20:30). “Folly is bound up in the heart of a child, but the rod of discipline drives it far from him” (22:15). Our sinful hearts may not have fleshed out a particular sin yet, but we are still in need of God’s discipline to purge evil from us.