Nechemyah 13:1-2

On that day they read in the Sefer Moshe in the ears of HaAm; and therein was found written, that the Ammoni and the Moavi should not come into the Kehal HaElohim forever, Because they met not the Bnei Yisroel with lechem and with mayim, but hired Balaam against them, that he should curse them; howbeit Eloheinu turned the kelalah into a brocha.