عَنِ ابْنِ عَبَّاسٍ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بَعَثَ مُعَاذًا إِلَى الْيَمَنِ فَقَالَ: «إِنَّك تَأتي قوما من أهل الْكتاب. فَادْعُهُمْ إِلَى شَهَادَةِ أَنْ لَا إِلَهَ إِلَّا اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ. فَإِنْ هُمْ أطاعوا لذَلِك. فَأَعْلِمْهُمْ أَنَّ اللَّهَ قَدْ فَرَضَ عَلَيْهِمْ خَمْسَ صَلَوَاتٍ فِي الْيَوْمِ وَاللَّيْلَةِ. فَإِنْ هم أطاعوا لذَلِك فأعلمهم أَن الله قد فرض عَلَيْهِم صَدَقَة تُؤْخَذ من أغنيائهم فَترد فِي فُقَرَائِهِمْ. فَإِنْ هُمْ أَطَاعُوا لِذَلِكَ. فَإِيَّاكَ وَكَرَائِمَ أَمْوَالِهِمْ وَاتَّقِ دَعْوَةَ الْمَظْلُومِ فَإِنَّهُ لَيْسَ بَيْنَهَا وَبَين الله حجاب»

Ibn 'Abbas reported God's messenger as saying when he sent Mu'adh to the Yemen, “You will come to folk who are people of a book, so invite them to testify that there is no god but God and that Muhammad is God's messenger. If they obey that, tell them God has made obligatory for them five times of prayer every twenty-four hours. If they obey that, tell them God has made obligatory for them sadaqa to be taken from their rich and handed over to their poor. If they obey that, avoid taking the best parts of their property; and regard the claim of him who is wronged, for there is no veil between it and God." (Bukhari and Muslim.)