Answer
In Exodus 34:7, God speaks to Moses and says that He punishes the children for the iniquity of the fathers “to the third and fourth generation.” The same idea is found earlier in Exodus 20:5 as God spoke the Ten Commandments to Moses. Here and in other verses, the word father can be understood as referring to both fathers and mothers. The NIV simply refers to “the sin of the parents.”
The specific sins of the father are not listed in Exodus 34:7. However, the context of the verse and book would suggest the sins of idolatry and unbelief. At this point in the book of Exodus, the Israelites have been freed from slavery in Egypt and are journeying to the Promised Land. In Exodus 32, Moses was on top of Mount Sinai meeting with God when the Israelites grew inpatient waiting for him to return. So they had Aaron the high priest make them an idol out of gold in the form of a calf, which they worshiped. When Moses came down from the mountain and saw the people’s idolatry, he was angry and broke the stone tablets upon which the Lord had written the Ten Commandments. God then commanded Moses to make new stone tablets and return to the top of Mount Sinai where He would once again give the law. That’s when God described Himself as “visiting the iniquity of the fathers upon the children and the children’s children to the third and the fourth generation” (Exodus 32:7, NKJV).
As a result of their idolatry, God punished the Israelites, and 3,000 of them were killed (Exodus 32:27–28). Their continued unbelief toward God led them to wander through the desert for 40 years, and that generation did not enter the Promised Land (Numbers 14:29–34). The consequences of these punishments would have been felt in the third and fourth generations of Israelites. Just as God promised in Exodus 34:7, the sins of the fathers were visited upon their descendants.
So, in the context of Exodus 34:7, the “sins of the father” can be understood as idolatry and unbelief. In other words, the Israelites did not trust that God would do what He promised in bringing them safely to the Promised Land.
It’s important to note that, even within the Mosaic Law, children were not required to suffer the penalty for their parents’ sins (see Deuteronomy 24:16). Nor was a child’s standing before God determined by the actions of his or her parents (see Ezekiel 18:1–32). However, there is no such thing as sin without consequence. When a parent sins, his or her children (and grandchildren) can expect to experience negative, earthly consequences for that sin. For example, if a father is an alcoholic, his children will not be punished for his sin; however, they will have to deal with the negative consequences of his actions, such as verbal abuse, a strained marriage with the mother, financial problems, and more.
Through Jesus and His death on the cross, all punishment for sin has been paid for once and for all and is not counted against those who have faith in Him (Romans 6:10; 1 Peter 3:18). In moments when we must deal with the consequences of other peoples’ sin, we can remember that God has given us the Holy Spirit as a comforter and helper (John 14:16–17) and that God has promised to work all things together for the good of those who love Him (Romans 8:28).