It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that when the Messenger of Allah (peace and blessings be upon him) sent Sayyiduna Mu’adh (may Allah be pleased with him) to Yemen, he said:“You are going to a people who are from the People of the Book, so invite them to testify that there is no deity except Allah, and that Muhammad (peace and blessings be upon him) is the Messenger of Allah. If they accept this from you, then inform them that Allah, the Exalted, has made five prayers obligatory upon them in every day and night. If they accept this from you, then inform them that Allah has made zakat obligatory upon them, to be taken from their wealthy and distributed among their poor. If they accept this from you, then avoid taking the best (most valuable) of their wealth, and beware of the supplication (curse) of the oppressed, for there is no barrier between it and Allah, the Exalted.”