Mutarrif bin Abdullah bin al-Shikhkhir reports from a Companion who was the governor of Kufah that he said in a sermon: "Giving this wealth is a trial, and withholding it is also a trial. That is why, when the Prophet (peace and blessings be upon him) occupied himself with it (that is, began distributing it), he would come down from the pulpit only after finishing it."
Ahmad recorded it; its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الزكاة / 4521