"I heard the Messenger of Allah say: 'It is a good fast to fast three days of each month".  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ صِيَامٌ حَسَنٌ ثَلاَثَةُ أَيَّامٍ مِنَ الشَّهْرِ  

[Machine] I heard the Messenger of Allah ﷺ saying: "Fasting is a shield from the punishment of Allah, just like a shield from fighting for one of you. And fasting is considered good for three days of every month."  

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ الصَّوْمُ جُنَّةٌ مِنْ عَذَابِ اللهِ كَجُنَّةِ أَحَدِكُمْ مِنَ الْقِتَالِ وَصِيَامٌ حَسَنٌ ثَلَاثَةُ أَيَّامٍ مِنْ كُلِّ شَهْرٍ  

"I heard the Messenger of Allah say: 'It is a good fast to fast three days of each month". (Using translation from Nasāʾī 2411)  

وَسَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ صِيَامٌ حَسَنٌ صِيَامُ ثَلَاثَةِ أَيَّامٍ مِنَ الشَّهْرِ  

" I heard the Messenger of Allah say: 'The month of patience ( Ramadan) and three days of each month is fasting for a lifetime."' (Sahih). (Using translation from Nasāʾī 2408)   

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ صَوْمُ شَهْرِ الصَّبْرِ وَثَلَاثَةِ أَيَّامٍ مِنْ كُلِّ شَهْرٍ يُذْهِبْنَ وَحَرَ الصَّدْرِ  

[Machine] I heard the Messenger of Allah ﷺ say, "Fasting is a shield, like a shield of one of you in battle." And I heard the Messenger of Allah ﷺ say, "Fasting for three days every month is a good deed."  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ «الصِّيَامُ جُنَّةٌ كَجُنَّةِ أَحَدِكُمْ مِنَ الْقِتَالِ» وَسَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ «صِيَامٌ حَسَنٌ ثَلَاثَةُ أَيَّامٍ مِنْ كُلِّ شَهْرٍ»  

[Machine] On the authority of the Prophet ﷺ who said, "The fasting is good. The fasting of three days each month is (equivalent to) continuous fasting."  

عَنِ النَّبِيِّ ﷺ قَالَ «صِيَامٌ حَسَنٌ صِيَامُ ثَلَاثَةِ أَيَّامٍ مِنْ كُلِّ شَهْرٍ»