Abdullah bin Umar reported,

I heard the Messenger of Allah ﷺ say, "The month is twenty-nine days."

Muslim 2507

Sahih

و حدثني حجاج بن الشاعر حدثنا حسن الأشيب حدثنا شيبان عن يحيى قال وأخبرني أبو سلمة أنه سمع

ابن عمر رضي الله عنهما يقول

ا سمعت رسول الله ﷺ يقول الشهر تسع وعشرون

مسلم 2507صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Fasting
Chapter
Obligation of fasting Ramadan upon sighting Hilal and breaking the fast upon sighting Hilal, and that if it is obscured at its beginning or end the month is completed as thirty days
Numbering
Darussalam 2507
Muslim 2507