It's true there are consequences for sin. But God determines those consequences and they vary according to a man's motives, opportunities, and influence (Luke 12:47-48).*
Some people prefer to differentiate between the words punish and discipline because there is no eternal punishment for believers. That's a wonderful truth!
However, the Bible warns believers of earthly punishment as well as earthly discipline.
For thousands of years, Christians never doubted this aspect of God's character. But modern culture defines love as unconditional tolerance and acceptance, and Christians have come to believe that God not only forgives their sins, He also overlooks their sins. Not true.
God is incredibly patient and merciful not punishing us to the extent we deserve (Psalm 103:8-14), but He still "disciplines those he loves, and he punishes each one he accepts as his child." Hebrews 12:6
The question we each must answer is this: Do we trust our loving God to know what's best for us (Revelation 3:19)?
* But we must be very careful not to assign blame when a person is going through hardship unless the hardship is a direct result of an obvious sin. See No Karma and What Did They Do to Deserve This?
1. God's punishment and judgment are perfect. They are never harsh, random, or illogical because they are part of His perfect love for us. He knows exactly what we need, and He will punish us if it is for our best good. A parent who never punishes his child doesn't really love the child because the child will never mature properly. The same is true for us as children of God.
Hebrews 12: 1-11: As for us, we have this large crowd of witnesses around us. So then, let us rid ourselves of everything that gets in the way, and of the sin which holds on to us so tightly, and let us run with determination the race that lies before us. 2 Let us keep our eyes fixed on Jesus, on whom our faith depends from beginning to end. He did not give up because of the cross! On the contrary, because of the joy that was waiting for him, he thought nothing of the disgrace of dying on the cross, and he is now seated at the right side of God's throne. 3 Think of what he went through; how he put up with so much hatred from sinners! So do not let yourselves become discouraged and give up.
4 For in your struggle against sin you have not yet had to resist to the point of being killed. 5 Have you forgotten the encouraging words which God speaks to you as his children? “My child, pay attention when the Lord corrects you, and do not be discouraged when he rebukes you. 6 Because the Lord corrects everyone he loves, and punishes everyone he accepts as a child.”
7 Endure what you suffer as being a father's punishment; your suffering shows that God is treating you as his children. Was there ever a child who was not punished by his father? 8 If you are not punished, as all his children are, it means you are not real children, but bastards. 9 In the case of our human fathers, they punished us and we respected them. How much more, then, should we submit to our spiritual Father and live! 10 Our human fathers punished us for a short time, as it seemed right to them; but God does it for our own good, so that we may share his holiness. 11 When we are punished, it seems to us at the time something to make us sad, not glad. Later, however, those who have been disciplined by such punishment reap the peaceful reward of a righteous life. GNT
The Greek word for punishment in Hebrews 12:6 is mastigóō and it literally means to whip, but it is used figuratively in this verse to mean God causing hardship or difficulty in a person's life in their best interest. This is why God's punishment is compared to a father who disciplines his son.
2. In Revelation 3:19, Jesus speaks a similar truth when addressing Christians who have grown cold in their faith.
Revelation 3:19: Those whom I love I reprove and discipline. So be zealous and repent.
In this verse, the Greek word for reprove means to correct and expose sin and the Greek word for discipline means training that can involve punishment.