"The Messenger of Allah used to enjoin fasting three days: The first Thursday, and Monday and Monday."  

كَانَ رَسُولُ اللَّهِ ﷺ يَأْمُرُ بِصِيَامِ ثَلاَثَةِ أَيَّامٍ أَوَّلِ خَمِيسٍ وَالاِثْنَيْنِ وَالاِثْنَيْنِ  

The apostle of Allah ﷺ used to fast three days every month: Monday, Thursday and Monday in the next week.  

كَانَ رَسُولُ اللَّهِ ﷺ يَصُومُ ثَلاَثَةَ أَيَّامٍ مِنَ الشَّهْرِ الاِثْنَيْنِ وَالْخَمِيسِ وَالاِثْنَيْنِ مِنَ الْجُمُعَةِ الأُخْرَى  

Hunaydah al-Khuza'i reported on the authority of her mother who said: I entered upon Umm Salamah and asked her about fasting. She said: The Messenger of Allah ﷺ used to command me to fast three days every month beginning with Monday or Thursday.  

كَانَ رَسُولُ اللَّهِ ﷺ يَأْمُرُنِي أَنْ أَصُومَ ثَلاَثَةَ أَيَّامٍ مِنْ كُلِّ شَهْرٍ أَوَّلُهَا الاِثْنَيْنِ وَالْخَمِيسِ  

The apostle of Allah ﷺ used to fast three days every month: Monday, Thursday and Monday in the next week. (Using translation from Abū Dāʾūd 2451)   

كَانَ رَسُولُ اللهِ ﷺ يَصُومُ ثَلَاثَةَ أَيَّامٍ مِنَ الشَّهْرِ الِاثْنَيْنِ وَالْخَمِيسَ وَالِاثْنَيْنِ مِنَ الْجُمُعَةِ الْأُخْرَى  

[Machine] The Messenger of Allah ﷺ used to command me to fast three days from the month: Monday, Thursday, and Thursday.  

كَانَ رَسُولُ اللهِ ﷺ يَأْمُرُنِي أَنْ أَصُومَ ثَلَاثَةَ أَيَّامٍ مِنَ الشَّهْرِ الِاثْنَيْنِ وَالْخَمِيسَ وَالْخَمِيسَ  

"عَنْ أُمِّ سَلَمَةَ قَالَتْ: كَانَ رَسُول اللهِ ﷺ يَأمُرنِي بِصِيَامِ ثَلاثَةِ أَيَّامٍ مِنْ كُلِّ شَهْر: أَوَّلُهَا الإثنان وَالْخَمِيس".