Abu Hurairah reported,

The Messenger of Allah ﷺ said, "Allah said, 'Every deed of the son of Adam is for him, except for fasting, for it is for Me and I shall reward him for it.' Fasting is a shield. When one of you is fasting, he should not speak indecently or raise his voice in argument. If someone insults him or tries to fight him, let him say, 'I am fasting.' By the One in whose hand is Muhammad's soul, the breath of the fasting person is more pleasant to Allah than the scent of musk. The fasting person has two moments of joy that he experiences, when he breaks his fast he rejoices, and when he meets his Lord he rejoices over his fasting."

Bukhari 1904

Sahih

حدثنا إبراهيم بن موسى أخبرنا هشام بن يوسف عن ابن جريج قال أخبرني عطاء عن أبي صالح الزيات أنه سمع

أبا هريرة رضي الله عنه يقول

قال رسول الله ﷺ قال الله كل عمل ابن آدم له إلا الصيام فإنه لي وأنا أجزي به والصيام جنة وإذا كان يوم صوم أحدكم فلا يرفث ولا يصخب فإن سابه أحد أو قاتله فليقل إني امرؤ صائم والذي نفس محمد بيده لخلوف فم الصائم أطيب عند الله من ريح المسك للصائم فرحتان يفرحهما إذا أفطر فرح وإذا لقي ربه فرح بصومه

البخاري 1904صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Fasting
Chapter
One who is reviled, should he say "I am fasting"
Numbering
Darussalam 1904
Bukhari 1904