Kommentar zu Dewarim 7:10

ומשלם לשנאיו אל פניו AND HE REPAYETH THEM THAT HATE HIM TO THEIR FACE [IN ORDER TO MAKE THEM PERISH] — i.e. during their lifetime (cf. Rashi on Genesis 11:28 s. v. על פני) he repayeth them their good recompense, in order to banish them from the future world (cf. Onkelos).

ומשלם לשונאיו, "and He repays them that hate Him." Why is the first half of this verse written in the plural, i.e "those who hate Him," whereas the individual who is the victim of this repayment is described in the singular? Perhaps the meaning is that unless G'd foresees that not only the individual who hates Him has sinned but also his children and children's children will continue to sin, He would forego repayment, (retribution), awaiting the penitence of the sinner's children. If, however, G'd foresees that the sinner begets only other sinners, He has no incentive to delay repaying such a sinner. This conforms to the principle ברא מזכה אבא, that "a son may confer a merit on his father."

ומשלם לשונאיו. retribution for its sins.