Sahih Bukhari Volume 004, Book 055, Hadith Number 615.

Narated By Abu Huraira : Allah's Apostle said, "It was said to Bani Israel, Enter the gate (of the town) with humility (prostrating yourselves) and saying: "Repentance", but they changed the word and entered the town crawling on their buttocks and saying: "A wheat grain in the hair."

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