The Messenger of Allah ﷺ said, "Every good deed the son of Adam performs is multiplied tenfold, up to seven hundred times, except fasting. It is for Me, and I alone will reward it. He gives up his desires for My sake and forsakes his food for My sake. The fasting person has two moments of joy, one when he breaks his fast and another when he meets his Lord . And the breath of the fasting person is more pleasing to Allah than the fragrance of musk."
حدثنا عبد الرزاق أخبرنا سفيان عن الأعمش عن ذكوان
قال رسول الله ﷺ كل حسنة يعملها ابن آدم تضاعف عشرا إلى سبع مائة ضعف إلا الصيام فهو لي وأنا أجزي به يدع شهوته من أجلي ويدع طعامه من أجلي فرحتان للصائم فرحة عند فطره وفرحة عند لقاء ربه عز وجل ولخلوف فم الصائم أطيب عند الله من ريح المسك
Its isnad is sahih. Zakwan is Abu Salih Samman. The hadith has already appeared as no. 7194 in similar form, narrated by Ibn Sirin from Abu Hurairah. But here there is an addition which we will point out below. In the previous narration, as in this one, part of it is a hadith qudsi, though this was not explicitly stated because it was obvious. Part of its meaning has already appeared, split into two hadiths, nos. 7485 and 7485m, narrated by Musa bin Yasar from Abu Hurairah, with the hadith qudsi made explicit by the phrase "Allah says" . In this narration there is the addition of the words "Two joys for the fasting person..." and so on, the meaning of which has already appeared briefly as part of this same meaning in no. 7174, narrated by Abu Salih from both Abu Hurairah and Abu Saeed together.The hadith was narrated by Muslim, nos. 316-317, including this addition, from Abu Muawiya, Waki, and Jareer, all of them from Amash, from Abu Salih. It was likewise narrated by Ibn Majah, no. 1638, from Abu Muawiya and Waki. A portion of it was also narrated with the same isnad as no. 3823, and Bukhari narrated it in a slightly abridged form, 13:389, from Abu Naeem, from Amash. Something similar was also narrated from Ataa, from Abu Salih. See also its meaning in the hadith of Ibn Masud, with a daif isnad, no. 4256.