The following is a brief article by R.C. Sproul Jr. Just read it!
God tells us in Exodus 20 that He will visit “the iniquity of the fathers upon the children to the third and fourth generations of those who hate Me,” (verse 5). That might settle the issue, but then God also told us this, “In those days they shall say no more: ‘ The fathers have eaten sour grapes, And the children’s teeth are set on edge.’” (Jeremiah 31:29). Does this mean that there was, in the old covenant, familial curses, and that in the new they no longer exist? I think not.
I would suggest instead that what was still is, and what is not, never was. God’s promise in Exodus 20 is not that He will send fresh judgment against one generation for the sins of another generation. God does not have beside His throne a box full of thunderbolts that He hurls down on sinners. Much less does He hurl down thunderbolts against someone’s great grandchildren. The consequences of our sin are much more organic than that, as are the results of our obedience.
Suppose that I suffered from covetousness. God is unlikely to, if I am outside the kingdom, send me boils to punish me. Neither is He likely, if I am inside the kingdom, to send me boils to coax me toward repentance. What He is far more likely to do, in either case, is afflict me with collection calls, repo men, crippling interest rates and foreclosure. Now suppose my sons grew up in this covetous household. Is it not more likely that they will learn covetousness from me? Will they not likely see the afflictions as normal life? They certainly are not likely to receive an inheritance that could bless them. They would, in this sense, live with the consequences of my sin, for multiple generations. My iniquity would be visited on them.
That said, if they in turn live covetous lives, will they be able to blame either God or me for the collections calls, repo men, etc? Of course not. They are still responsible to be financially responsible. They are in like manner free to live in gratitude, and to end the cycle.
Those who promote the notion of “familial curses” are correct to note that our sins are not hermetically sealed, affecting only the sinner. (Remember that multiple “innocent” families lost husbands and fathers at Ai because of Achan’s sin at Jericho (Joshua 7:4).) God does indeed deal with us corporately, not just in the family but in churches, communities and nations. Those who think there is some sort of mystical cure, beyond repentance, are, I fear, mistaken.
In the end, if we are suffering and wondering why, the last answer we should come to is, “It is my ancestor’s fault.” On the other hand, when we are tempted to sin, we ought never to lose sight that the consequences certainly can outlive us, and afflict those we love. Thus I pray often that God would spare my children from the fruit of my sins. In either case the answer is to repent and to give thanks. We all enjoy so much more than we are due. And even suffering, for the believer, is blessing. We are to count it all joy.