(17) باب ذِكْرِ الاِخْتِلاَفِ عَلَى يَحْيَى بْنِ أَبِي كَثِيرٍ فِي خَبَرِ أَبِي سَلَمَةَ فِيهِ
It was narrated from Ibn 'Umar that the Prophet said:
"We are an unlettered Ummah, we do not use astronomical counting or computation. The month is like this, and this, and this," he did three times, showing it as twenty-nine.
Reference: Sunan an-Nasa'i 2140
In-book reference: Book 22, Hadith 51
English translation: Vol. 3, Book 22, Hadith 2142