Affliction

"[Jerusalem's] adversaries are the chief, her enemies prosper; for the Lord hath afflicted her for the multitude of her transgressions..." Lamentations 1:5a

As Christians, we must never lose the sense of what is "behind the scenes." We practice the sense pretty well sometimes in spiritual warfare: it is not our friends, family, co-workers, or bosses; not strangers, circumstances, or our imagination. Something else really is "in the way," as Lewis put it. In our way is an enemy that hates us and longs for our destruction (of course, see I Peter 5:8).
It is easy for us, however, to assume that ALL affliction comes from the enemy. This is not a cliche slap at prosperity gospel: you can believe that Satan is responsible for all your problems and also believe that God is behind it somewhere. In a case like that (Satan/demonic affliction with God behind it) you are in the position of Job: your affliction comes in order to test your faith, i.e., to see where your reality lies (whether with yourself and circumstances or God and His will).
The problem is that as Christians we can slip into the dangerous position of believing Hell is responsible for ALL of our problems, and hence ALL affliction is a testing of our faith. This is not true. There are two positions of affliction: one is of Job, affliction to test faith and correctly focus your reality; the other is the position of Jerusalem, where affliction comes because of your "transgressions."
In the first position, God is the Ultimate but not Immediate source of your affliction; the Immediate source is the demonic powers. In the second position, however, God is all in all, the Ultimate and Immediate source: "The Lord hath afflicted...for the multitude of transgressions."
When Christians slip into the deceptive stance of always being in the first position, the truth that God must punish sin is lost to them in regards to themselves. They surely see that truth in the lives of other's, but in their own life all affliction is a test of faith and not rebuttals from God, the Immediate affliction of the Lord.
"For the wages of sin is death..." (Rom. 6:32a) As with all overstated verses, the punch and the power gets lost in the telling. We must never forget that sin ALWAYS brings death (see also Rom. 5:12), and that does not change when you are redeemed into God's family through Christ's death and resurrection. When you are redeemed, you are no longer sold under sin, and therefore no longer held to its ultimate end, i.e., eternal death. But the NATURE of sin does not change: it always brings death. This is not a cruel joke God played on humanity; it is simply a fact, an absolute, the way things ARE. Sin cannot help but bring death, because sin is (as Dorothy Sayers put it) choosing the "not-God," and anything that is not God (that is not the way, truth, and life) is confusion, lies, and death. James tells us that wisdom comes from God, and in Proverbs wisdom says, "All they that hate me love death." In the end of Deuteronomy, God tells his children that there are only two paths that He has set before them: life and death. Those are our choices: life or death, God or everything else. And as a Christian, if you sin, if you willful choose the not-God, then as Oswald Chambers put it, you "work the death sentence on yourself," and God will not let it stand.
He is not cruel in this. He is being two things that He cannot help but be (because they are a part of His nature): He is being Holy (because holiness cannot tolerate sin: the Holy God sent His Holy Law to kill sin), and He is being Love (Proverbs 3:11-12). The beauty of being a redeemed child of God is that God deals with you in holiness AND love, an impossibility made possible through Christ (more on THAT subject in another note). If you were not His child, he would only deal with you in holiness, and the end dealing of holiness with sin is to cast it into outer darkness.
As His child, however, God will send affliction on your for one of two reasons: (1) to test your faith; or (2) to punish sin, because His holiness will not tolerate it, and His love will not let you stay fallen in the mire (Heb. 12:6-8). God sends affliction for our good (Rom. 8:38): if we are strong, He will make us stronger; if we fall, He will pick us up and whip all the filth off of us in the process.