Psalms 106:6

Here begins a penitential confession of sin, which was in a special manner seasonable now that the church was in distress; for thus we must justify God in all that he brings upon us, acknowledging that therefore he has done right, because we have done wickedly; and the remembrance of former sins, notwithstanding which God did not cast off his people, is an encouragement to us to hope that, though we are justly corrected for our sins, yet we shall not be utterly abandoned. I. God's afflicted people here own themselves guilty before God (Psa 106:6): "We have sinned with our fathers, that is, like our fathers, after the similitude of their transgression. We have added to the stock of hereditary guilt, and filled up the measure of our fathers' iniquity, to augment yet the fierce anger of the Lord," Num 32:14; Mat 23:32. And see how they lay a load upon themselves, as becomes penitents: "We have committed iniquity, that which is in its own nature sinful, and we have done wickedly; we have sinned with a high hand presumptuously." Or this is a confession, not only of their imitation of, but their interest in, their fathers' sins: We have sinned with our fathers, for we were in their loins and we bear their iniquity, Lam 5:7. II.

— Matthew Henry's Concise Commentary (public domain)