When the Messenger of Allah ﷺ commanded us to give in charity, Abu Aqeel donated half a saa, and another man brought something much greater than that. The hypocrites remarked, "Allah has no need of this man's charity, and the other one only did what he did to be seen by people." So this verse was revealed, "Those who criticize the believers who give charity voluntarily and ridicule those who find nothing to give except their meager effort" [Tawbah 9:79].
أخبرنا بشر بن خالد قال حدثنا غندر عن شعبة عن سليمان عن أبي وائل
لما أمرنا رسول الله ﷺ بالصدقة فتصدق أبو عقيل بنصف صاع وجاء إنسان بشيء أكثر منه فقال المنافقون إن الله عز وجل لغني عن صدقة هذا وما فعل هذا الآخر إلا رياء فنزلت {الذين يلمزون المطوعين من المؤمنين في الصدقات والذين لا يجدون إلا جهدهم}
Sourcing, Bukhari related it in tafsir, in the chapter on the saying of Allah, "Those who criticize the volunteers among the believers regarding," etc., hadith no. 1018, concerning charitable donations, hadith no. 4668, and Muslim, in zakat, in the chapter on carrying goods for wages and giving them as charity, via Bishr bin Khalid, and it is in Al-Kubra, hadith no. 2309.Sulayman is Ibn Mihran Amash.