These are the words which Moses spoke to all Israel (Deut. 1:1) Comments Rashi: "Since these are words of reproof...he mentions them [only] in allusion out of respect for Israel." However, we find that the very same sins Moses only hints at here are explicitly detailed later on in the Torah. This apparent conflict is resolved by the Midrash: As soon as the Jews heard Moses' words of rebuke they sincerely repented; when a person repents out of love, "his deliberate sins are transformed into mitzvot." Thus, after the Jews repented Moses was free to enumerate their sins, as by doing so he was adding to their merits. (Imrei Elimelech)
Reprinted from the Parashat Devarim 5761/2001 edition of L’Chaim.