Umm al-Mu'minin Sayyidah Umm Salamah (may Allah be pleased with her) narrates that while the Prophet (peace and blessings be upon him) was in her house, with some of his Companions sitting with him talking, a man came and said: "O Messenger of Allah, how much is the zakah on such-and-such an amount of dates?" The Messenger of Allah (peace and blessings be upon him) said: "Such-and-such." The man said: "So-and-so transgressed against me and took such-and-such from me," that is, he took one sa' more. The Messenger of Allah (peace and blessings be upon him) said: "Then how will it be with you when those who transgress against you even more severely than this come to collect from you?" The people began discussing it and the matter weighed heavily on them, until one of them said: "O Messenger of Allah, if a man is away from you with his camels, livestock and crops, and he pays the zakah of his wealth, but the due is exceeded against him, what should he do while he is absent?" The Messenger of Allah (peace and blessings be upon him) said: "Whoever pays the zakah of his wealth willingly, for the pleasure of Allah and the Home of the Hereafter, and conceals nothing of his wealth, establishes the prayer and pays the zakah, and then (unjustly) his right is transgressed, and he takes up his weapon and fights for the sake of his right and is killed, he is a martyr." This hadith is sahih on the condition of the two Shaykhs, but they did not record it.