Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that when the Messenger of Allah (peace and blessings be upon him) sent Sayyiduna Mu’adh bin Jabal (may Allah be pleased with him) towards Yemen (as governor), he said:“Indeed, you are going to a people from among the People of the Book. When you reach them, invite them to testify that there is no deity worthy of worship except Allah and that Muhammad (peace and blessings be upon him) is the Messenger of Allah. If they obey you in this, then inform them that Allah, the Exalted, has made five prayers obligatory upon them in every day and night. If they obey you in this, then inform them that Allah has made zakat obligatory upon their wealth, to be taken from their rich and distributed among their poor. If they obey you in this, then avoid taking the best of their wealth, and beware of the supplication of the oppressed, for there is no barrier between his supplication and Allah, the Exalted.”