Charles Ellicott Commentary Deuteronomy 32:35

"Vengeance is mine, and recompense, At the time when their foot shall slide: For the day of their calamity is at hand, And the things that are to come upon them shall make haste." — Deuteronomy 32:35 (ASV)

To me belongeth vengeance, and recompence. —In the Epistle to the Hebrews (Hebrews 10:30) this sentence is quoted with the first clause of Deuteronomy 32:36, For we know Him that said, Vengeance belongeth unto me. I will recompense, saith the Lord. And so in Romans 12:19.

Their foot shall slide in due time. —Rather, for the time when their foot shall slide.