It is narrated from Sayyiduna Qays bin Sa'd bin Ubadah al-Ansari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) sent him as a collector of zakah. His father (Sa'd bin Ubadah) said: Do not go until you have renewed your covenant with the Messenger of Allah (peace and blessings be upon him). So he came to him (peace and blessings be upon him), and he (peace and blessings be upon him) said: "O Qays! Let it not be that you come on the Day of Resurrection with a camel on your neck, groaning, or a cow, lowing, or a sheep, bleating. And do not be like 'Abu Righal'." Sayyiduna Sa'd asked: O Messenger of Allah! Who was Abu Righal? He (peace and blessings be upon him) said: "He was a zakah collector sent by Sayyiduna Salih (peace be upon him). In Ta'if he came across a man who had a small flock of nearly a hundred sheep, all of them dry except for one, and he had a small son who had no mother, whose sustenance was the milk of that sheep. The owner of the sheep asked: Who are you? He said: I am the envoy of the Messenger of Allah. So he welcomed him and said: These are my sheep; take whichever of them you like. He looked at the milking sheep and said: This one. The man said: This boy, as you see, has no food or drink other than it. He said: If you love milk, I love it too. The man said: Take two sheep in its place. But he refused. The man kept increasing and offering until he offered him five dry sheep in its place, but he still refused. When the man saw that, he took up his bow, shot him and killed him, and said: No one ought to take this news to the Messenger of Allah before me. So the owner of the sheep came to Salih (peace be upon him) and informed him, and Salih (peace be upon him) said: O Allah, curse Abu Righal! O Allah, curse Abu Righal!" Hearing this, Sayyiduna Sa'd bin Ubadah said: O Messenger of Allah! Excuse Qays from this responsibility. This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs did not record it, and there is also an abridged supporting narration (shahid) for it on the condition of the two Shaykhs:

It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) sent Sa'd bin Ubadah as a collector of zakah and said: "O Sa'd! Beware of coming on the Day of Resurrection carrying on your neck a camel that is groaning." He said: (If there is such a danger, then) I will not take up this post. So he (peace and blessings be upon him) excused him.

Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) states: The Prophet (peace and blessings be upon him) sent me to collect zakah. I passed by a man, and he gathered his wealth before me, and nothing was due from him except a one-year-old she-camel (bint makhad). I said: Give a one-year-old she-camel; that is your zakah. He said: That gives neither milk nor can it be ridden; take this best, young and fat she-camel of mine instead. I said: I cannot take what I have not been commanded to take. The Messenger of Allah (peace and blessings be upon him) is near you; if you wish, go to him and offer him what you have offered me. If he (peace and blessings be upon him) accepts it, I will accept it, and if he (peace and blessings be upon him) returns it, I will return it. He said: I will do so. So he set out with me, bringing the she-camel he had offered me, until we reached the Messenger of Allah (peace and blessings be upon him). He said: O Prophet of Allah! Your envoy came to me to take the zakah of my wealth. By Allah! Never before has the Messenger of Allah (peace and blessings be upon him) or any envoy of his come for (the zakah of) my wealth. I gathered my wealth for him, and he said that a one-year-old she-camel is due from me, but that gives neither milk nor can it be ridden. I offered him a large she-camel to take, but he refused. O Messenger of Allah! This is that she-camel, which I have brought to you, so accept it. The Messenger of Allah (peace and blessings be upon him) said: "What was due from you was that (one-year-old she-camel), but if you wish to give this better she-camel willingly, Allah will reward you for it and we will accept it." He said: O Messenger of Allah! Here is that she-camel; I have brought it to you, so accept it. So the Messenger of Allah (peace and blessings be upon him) ordered that it be taken and prayed for blessing in his wealth. This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs did not record it.