It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him): Hasan bin Ali (may Allah be pleased with them both) picked up a date from the dates of charity and put it in his mouth. The Messenger of Allah (peace and blessings be upon him) said to him: "Do not take it, do not take it." So he spat it out. The Prophet (peace and blessings be upon him) said: "Do you not know that charity is not lawful for us?"
Hadith Referenceمسند اسحاق بن راهويه / كتاب الزكوٰة / 274
Hadith Takhrij«بخاري ، كتاب الزكاة ، باب ما يذكر فى الصدقة للنبي صلى الله عليه وسلم ، رقم : 1491 . مسلم ، كتاب الزكاة ، باب تحريم الزكاة على رسول الله صلى الله عليه وسلم صلى الله عليه واله وسلم ، رقم : 69 . مسند احمد : 409/2 . سنن دارمي ، رقم : 1642 .»
Muhammad bin Ziyad narrated: I heard Sayyiduna Abu Hurairah (may Allah be pleased with him) narrate: Hasan bin Ali (may Allah be pleased with both of them) took (a date), then he mentioned as in the previous hadith.
Hadith Referenceمسند اسحاق بن راهويه / كتاب الزكوٰة / 275
Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated: Dates of charity were presented to the Messenger of Allah (peace and blessings be upon him). He (peace be upon him) lifted Hasan or Husayn (may Allah be pleased with them both) onto his shoulder, and their saliva began to flow. He saw that there was a date from the charity dates in their mouth. So he shook them, and they spat it out. The Messenger of Allah (peace and blessings be upon him) said: "Do you not know, charity is not lawful for us."
Hadith Referenceمسند اسحاق بن راهويه / كتاب الزكوٰة / 276
Hadith Takhrij«مسند احمد : 279/2 . قال شعيب الارناوط ، اسناده صحيح»