It is narrated from Sayyiduna Adi bin Amirah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "O people! Whoever does any work for us and then conceals from us even a needle or anything bigger than it, he is a betrayer; he will come on the Day of Resurrection with that thing (with him)." A dark-skinned man from the Ansar stood up, the narrator says: it is as if I am looking at him now, and he said: "Take back your assignment from me." He (peace and blessings be upon him) said: "Why?" He said: "You have just given a warning about it." So he (peace and blessings be upon him) said: "I say it even now: whomever we appoint over some work, let him bring everything, small and large; what he is given from it he may take, and what he is forbidden from he must refrain from."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13172
Sayyiduna Adi bin Amirah al-Kindi (may Allah be pleased with him) says: I heard the Messenger of Allah (peace and blessings be upon him) saying, like the hadith that has passed before.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13173
It is narrated from Sayyiduna Abu Humayd al-Sa'idi (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) appointed someone as collector over the charity. When the collector came, he said: "O Messenger of Allah! This is for you, and this is for me, which was given to me as a gift." So the Prophet (peace and blessings be upon him) said: "If you had sat in the house of your father and mother, would these gifts have been given to you or not?" Then in the evening he (peace and blessings be upon him) stood on the pulpit after the prayer, bore witness (to Allah's oneness) and praised and extolled Allah as He deserves. Then he said: "What is the matter with the collectors (who collect charity), that we appoint them over the charities and they say: This is our gift and this is the charity wealth? Why did he not sit in the house of his father and mother and see whether gifts would be given to him or not? By the One in whose Hand is my soul! None of you accepts anything from it except that he will bring it on the Day of Resurrection: if it is a camel, he will be carrying it on his neck and it will be groaning; if it is a cow, it will be lowing; and if it is a goat, he will bring it too and it will be bleating. Indeed, I have conveyed all these things to you."
Abu Humayd (may Allah be pleased with him) said: Then the Prophet (peace and blessings be upon him) raised his hand until we could see the whiteness of his armpits. Abu Humayd (may Allah be pleased with him) said: Zayd bin Thabit (may Allah be pleased with him) also heard this from the Messenger of Allah (peace and blessings be upon him), so ask him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13174
Uqbah bin Amir (may Allah be pleased with him) says that I heard the Messenger of Allah (peace and blessings be upon him) saying: "The one who (unjustly) takes taxes will never enter Paradise."
By "tax" (maks) is meant the reduction by which the collector diminishes the rights of the poor and does not give them their full rights. (When he does this) he will be a "tax-taker", and one should fear the sin upon him and its consequence. And Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13175