The LORD is slow to anger, abounding in love and forgiving sin and rebellion. Yet he does not leave the guilty unpunished; he punishes the children for the sin of the parents to the third and fourth generation.'-Numbers 14:18
I admit this verse has been heavy on me over the last few years and I think of it often. To me, it's not so much that the Lord is punishing the children for the sins of the father. I read it that the children are bearing the consequences.
If your husband is from a family full of abuse, incest, infidelity, then his "normal" was skewed. What he learned from a young age, was wrong. So he was, in a sense, punished for the sins of his parents. And then he grew up and now your children are being affected by his behavior. But it isn't a cycle that can't be broken.
I think the other important thing to remember about this verse is it is Old Testament. The Old Testament can be difficult to understand. I have a hard time with some of the psalms in particular. David prays often to destroy his enemies in battle. I don't know what to make of some of them.
We know that Jesus came to fulfill the scriptures and create a new covenant.
Jeremiah:
Behold, the days are coming, declares the Lord, when I will make a new covenant with the house of Israel and the house of Judah, 32 not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the Lord. 33 For this is the covenant that I will make with the house of Israel after those days, declares the Lord: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people. 34 And no longer shall each one teach his neighbor and each his brother, saying, ‘Know the Lord,’ for they shall all know me, from the least of them to the greatest, declares the Lord. For I will forgive their iniquity, and I will remember their sin no more.”
Hebrews:
For this reason Christ is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance--now that he has died as a ransom to set them free from the sins committed under the first covenant.
John:
His disciples asked Him, “Rabbi, who sinned, this man or his parents, that he would be born blind?” 3Jesus answered, “It was neither that this man sinned, nor his parents; but it was so that the works of God might be displayed in him.
In this last verse, the disciples ask whose sin because of that numbers verse. But Jesus corrects them. We may not understand why we suffer or what purpose we have. But God knows. God knew from the day the blind man was born, that his life was meant to glorify and testify to the majesty of God. I'm sure he miserably wondered why him? Why was he born blind? And then, finally, his site was miraculously restored and we read his story thousands of years later as a testament to the majesty of Jesus.
Sorry, this is long and i'm no theologian, but I think the numbers verse is often taken out of context. Before Jesus, before the Holy Spirit was sent, God dealt with his people differently. Once Jesus fulfilled the old covenant, He created a new one.