The Five Books Against Marcion by Tertullian
Chapter XV.--The Severity of God Compatible with Reason and Justice When Inflicted, Not Meant to Be Arbitrary, But Remedial.
Consider well, then, before all things the justice of the Judge; and if its purpose be clear, then the severity thereof, and the operations of the severity in its course, will appear compatible with reason and justice. Now, that we may not linger too long on the point, (I would challenge you to) assert the other reasons also, that you may condemn the Judge's sentences; extenuate the delinquencies of the sinner, that you may blame his judicial conviction. Never mind censuring the Judge; rather prove Him to be an unjust one. Well, then, even though He required the sins of the fathers at the hands of the children, the hardness of the people made such remedial measures necessary for them, in order that, having their posterity in view, they might obey the divine law. For who is there that feels not a greater care for his children than for himself? Again, if the blessing of the fathers was destined likewise for their offspring, previous to any merit on the part of these, why might not the guilt of the fathers also redound to their children? As was the grace, so was the offence; so that the grace and the offence equally ran down through the whole race, with the reservation, indeed, of that subsequent ordinance by which it became possible to refrain from saying, that |the fathers had eaten a sour grape, and the children's teeth were set on edge:| in other words, that the father should not bear the iniquity of the son, nor the son the iniquity of the father, but that every man should be chargeable with his own sin; so that the harshness of the law having been reduced after the hardness of the people, justice was no longer to judge the race, but individuals. If, however, you accept the gospel of truth, you will discover on whom recoils the sentence of the Judge, when requiting on sons the sins of their fathers, even on those who had been (hardened enough) to imprecate spontaneously on themselves this condemnation: |His blood be on us, and on our children.| This, therefore, the providence of God has ordered throughout its course, even as it had heard it.