Musnad Ahmad 25256

"When the Messenger of Allah would lie down, he would place his right hand under his right cheek, and he used to fast on Mondays and Thursday."

إِذَا أَخَذَ مَضْجَعَهُ جَعَلَ كَفَّهُ الْيُمْنَى تَحْتَ خَدِّهِ الأَيْمَنِ وَكَانَ يَصُومُ الاِثْنَيْنَ وَالْخَمِيسَ ‏.‏

Narrated by Hafsa

‘A'isha said that God’s messenger used to fast on Mondays and Thursdays. Tirmidhi and Nasa’i transmitted it.

وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَصُومُ الِاثْنَيْنِ وَالْخَمِيس. رَوَاهُ التِّرْمِذِيّ وَالنَّسَائِيّ

Narrated by Ā’ishah + 1 other version

He said that the Prophet used to fast on Mondays and Thursdays, and when someone remarked on this to him he said, “On Monday and Thursday God forgives every Muslim except two who are at variance, for He says they must be left till they make peace with one another.” Ahmad and Ibn Majah transmitted…

" إِنَّ يَوْمَ الِاثْنَيْنِ وَالْخَمِيسِ يَغْفِرُ اللَّهُ فِيهِمَا لِكُلِّ مُسْلِمٍ إِلَّا ذَا هَاجِرَيْنِ يَقُولُ: دَعْهُمَا حَتَّى يصطلحا "

Narrated by Abu Hurayrah + 1 other version

"The Prophet used to fast the ten (days), and three days of each month: Monday and Thursday."

يَصُومُ الْعَشْرَ وَثَلاَثَةَ أَيَّامٍ مِنْ كُلِّ شَهْرٍ الاِثْنَيْنِ وَالْخَمِيسَ ‏.‏