Abdullah bin Umar reported,

The Messenger of Allah ﷺ said, "The month is like this, like this, and like this," and he clapped his hands together twice with all the fingers of both hands, and on the third clap he held back the thumb of either his right or his left hand.

Muslim 2509

Sahih

و حدثنا عبيد الله بن معاذ حدثنا أبي حدثنا شعبة عن جبلة قال سمعت

ابن عمر رضي الله عنهما يقول

ا قال رسول الله ﷺ الشهر كذا وكذا وكذا وصفق بيديه مرتين بكل أصابعهما ونقص في الصفقة الثالثة إبهام اليمنى أو اليسرى

مسلم 2509صحيح
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 2509
Muslim 2509