Sahih Muslim
Sahih Muslim 1157 d
The Prophet's Fasts at times other than Ramadan; and it is recommended to ensure that no month is free of fasting
Arabic hadith text
وَحَدَّثَنِيهِ عَلِيُّ بْنُ حُجْرٍ، حَدَّثَنَا عَلِيُّ بْنُ مُسْهِرٍ، ح وَحَدَّثَنِي إِبْرَاهِيمُ بْنُ مُوسَى، أَخْبَرَنَا عِيسَى بْنُ يُونُسَ، كِلاَهُمَا عَنْ عُثْمَانَ بْنِ حَكِيمٍ، فِي هَذَا الإِسْنَادِ . بِمِثْلِهِ
Translation
The same hadith as the previous hadith has been transmitted through another chain.