Ramadan is the "month of patience"

The father or Uncle of Mujibah al-Bahiliyyah visited the Messenger of Allah ﷺ. He then went away and came to him (again) after one year when his condition and appearance had changed. He said: Messenger of Allah, do you not recognize me? He asked: Who are you? He replied: I am al-Bahili who came to you last year. He said: What has changed you? You were looking well, then you were good in appearance? He said: I have only food at night since I departed from you.

Thereupon the Messenger of Allah ﷺ said: Why did you torment yourself? Fast during Ramadan (the month of patience) and fast for one day every month. He said: Increase it for me, for I have (more) strength. He said: Fast two days. He again said: Increase it for me. He said: Fast three days. He again said: Increase it for me. He said: Fast during the inviolable months and then stop; fast during the inviolable months and then stop; fast during the inviolable months and then stop. He indicated by his three fingers, and joined them and then opened them.

أَنَّهُ أَتَى رَسُولَ اللَّهِ ﷺ ثُمَّ انْطَلَقَ فَأَتَاهُ بَعْدَ سَنَةٍ وَقَدْ تَغَيَّرَتْ حَالَتُهُ وَهَيْئَتُهُ فَقَالَ: يَا رَسُولَ اللَّهِ أَمَا تَعْرِفُنِي؟ قَالَ: «وَمَنْ أَنْتَ؟» قَالَ: أَنَا الْبَاهِلِيُّ الَّذِي جِئْتُكَ عَامَ الأَوَّلِ۔ قَالَ: «فَمَا غَيَّرَكَ وَقَدْ كُنْتَ حَسَنَ الْهَيْئَةِ؟» قَالَ: مَا أَكَلْتُ طَعَامًا إِلاَّ بِلَيْلٍ مُنْذُ فَارَقْتُكَ۔ فَقَالَ رَسُولُ اللَّهِ ﷺ: «لِمَ عَذَّبْتَ نَفْسَكَ؟»

ثُمَّ قَالَ: «صُمْ شَهْرَ الصَّبْرِ، وَيَوْمًا مِنْ كُلِّ شَهْرٍ۔» قَالَ: زِدْنِي فَإِنَّ بِي قُوَّةً۔ قَالَ: «صُمْ يَوْمَيْنِ۔» قَالَ: زِدْنِي۔ قَالَ: «صُمْ ثَلاَثَةَ أَيَّامٍ۔» قَالَ: زِدْنِي۔ قَالَ: «صُمْ مِنَ الْحُرُمِ وَاتْرُكْ، صُمْ مِنَ الْحُرُمِ وَاتْرُكْ، صُمْ مِنَ الْحُرُمِ وَاتْرُكْ۔» وَقَالَ بِأَصَابِعِهِ الثَّلاَثَةِ فَضَمَّهَا ثُمَّ أَرْسَلَهَا