Sayyiduna Jarir bin Abdullah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "When the zakah collector comes to you, let him not part from you until he is pleased (give such wealth that he is pleased with)."
Imam al-Shafi'i (may Allah have mercy on him) said: Allah knows best, but it means that they should pay him in full, willingly, and not put him off; not that they should give him from their wealth what is not due from them. It is this that he commands them and commands the collector. And what Imam al-Shafi'i (may Allah have mercy on him) said would be plausible, were it not for the addition in the narration of Abd al-Rahman bin Hilal al-Absi.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7529