Charles Ellicott 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)

Fathers. — The sweet of vengeance lies in its completeness. The curse must strike backwards as well as forwards, and the root as well as the branch be destroyed. Undoubtedly, the Mosaic Law, which proclaimed that the iniquity of the fathers should be visited on the children, suggested the form of the imprecation.

Sin of his mother. — Is the necessity of the parallelism sufficient to account for this mention of the mother, or is some definite circumstance in the poet’s thought? The theory which makes this portion of the psalm (Psalms 109:6–20) a quotation of curses really uttered by Shimei against David finds an allusion to the Moabitish descent on the mother’s side. (Compare the Rabbinical explanation of Psalms 51:5.)