Abdullah bin Shaqiq reported,

I asked Ayesha رضي الله عنها, "Did the Messenger of Allah ﷺ ever fast an entire month?"She replied, "I do not know of him fasting an entire month except Ramadan, nor breaking his fast for an entire month without fasting some of it, until he passed away ﷺ."

Muslim 2718

Sahih

و حدثنا عبيد الله بن معاذ حدثنا أبي حدثنا كهمس

عن عبد الله بن شقيق قال

قلت لعائشة رضي الله عنها أكان رسول الله ﷺ يصوم شهرا كله قالت ما علمته صام شهرا كله إلا رمضان ولا أفطره كله حتى يصوم منه حتى مضى لسبيله ﷺ

مسلم 2718صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Fasting
Chapter
Fasting of the Prophet ﷺ outside Ramadan and the recommendation not to let a month pass without fasting
Numbering
Darussalam 2718
Muslim 2718