Narrated Ibn `Abbas:
When the Prophet sent Mu`adh to Yemen, he said to him, "You are going to a nation from the people
of the Scripture, so let the first thing to which you will invite them, be the Tauhid of Allah. If they
learn that, tell them that Allah has enjoined on them, five prayers to be offered in one day and one
night. And if they pray, tell them that Allah has enjoined on them Zakat of their properties and it is to
be taken from the rich among them and given to the poor. And if they agree to that, then take from
them Zakat but avoid the best property of the people."