The Prophet ﷺ used to fast on Mondays and Thursdays. Someone asked, "Messenger of Allah, why do you fast on Mondays and Thursdays?"He replied, "On Mondays and Thursdays Allah forgives every Muslim, except for two who have severed ties with one another. He says, 'Leave these two until they reconcile.'"
حدثنا العباس بن عبد العظيم العنبري حدثنا الضحاك بن مخلد عن محمد بن رفاعة عن سهيل بن أبي صالح عن أبيه
أن النبي ﷺ كان يصوم الاثنين والخميس فقيل يا رسول الله إنك تصوم الاثنين والخميس فقال إن يوم الاثنين والخميس يغفر الله فيهما لكل مسلم إلا مهتجرين يقول دعهما حتى يصطلحا
No references are available.
Its isnad is hasan. Tirmidhi transmitted it, Book of Fasting, Chapter on What Has Been Said Regarding Fasting on Monday and Thursday, no. 747, from the hadith of Abu Asim, from Dahhak, with the wording that the Messenger of Allah ﷺ said, "Deeds are presented on Monday and Thursday, and I love that my deeds be presented while I am fasting." Tirmidhi said, hasan gharib. Ahmad transmitted it, 2/329, from Abu Asim, from him, at greater length, and Busiri and Ibn Mulaqqin graded it sahih.