Authentic
graded by Al-Albani
Mishkat al-Masabih 1893
وَعَنْ جَابِرٍ وَحُذَيْفَةَ قَالَا: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «كُلُّ مَعْرُوف صَدَقَة»
Jabir and Hudhaifa reported God’s messenger as saying, “Every act of kindness is sadaqa.” (Bukhari and Muslim.)
Cited in Mishkat al-Masabih (No. 1893).