Albert Barnes Commentary Psalms 109:14

"Let the iniquity of his fathers be remembered with Jehovah; And let not the sin of his mother be blotted out." — Psalms 109:14 (ASV)

Let the iniquity of his fathers—Of his ancestors.

Be remembered with the Lord—Or, by the Lord. The doctrine of the Bible is that God visits the iniquities of the fathers upon the children unto the third and fourth generation of them that hate him (Exodus 20:5); the fact is that children and children’s children often suffer from the errors, the crimes, and the follies of their parents, as in the case of intemperance, murder, and treason (compare the notes at Romans 5:12 and following); and the prayer here is that this regular effect of sin might follow in this instance; that these consequences might not be arrested by divine interposition.

And let not the sin of his mother be blotted out—This is probably added to complete the parallelism: the sin of his father and his mother. There may, however, if this is a composition of David, be a similar allusion to that which occurs in Psalm 51:5: Behold, I was shapen in iniquity, and in sin did my mother conceive me. The prayer is that whatever effects might properly follow from the fact that his mother was a sinner—either in some special sense, or in the general sense that all are sinners—might come upon him.