The sentence on Moses was not passed when the people rebelled during their first encampment at Kadesh, but some 37 years later, when they had re-assembled in the same neighborhood at Meribah (see the Numbers 20:13 note). He alludes to it here as having happened not many months previously, bearing on the facts which were for his purpose in pricking the conscience of the people.
Related Commentaries of Deuteronomy 1:37
Deuteronomy 1:37
37 Also the LORD was angry with me for your sakes, saying, Thou also shalt not go in thither.