"‏ إِنَّكَ سَتَأْتِي قَوْمًا مِنْ أَهْلِ الْكِتَابِ، فَإِذَا جِئْتَهُمْ فَادْعُهُمْ إِلَى أَنْ يَشْهَدُوا أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ، وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ، فَإِنْ هُمْ طَاعُوا لَكَ بِذَلِكَ فَأَخْبِرْهُمْ أَنَّ اللَّهَ قَدْ فَرَضَ عَلَيْهِمْ خَمْسَ صَلَوَاتٍ فِي كُلِّ يَوْمٍ وَلَيْلَةٍ، فَإِنْ هُمْ طَاعُوا لَكَ بِذَلِكَ، فَأَخْبِرْهُمْ أَنَّ اللَّهَ قَدْ فَرَضَ عَلَيْكُمْ صَدَقَةً، تُؤْخَذُ مِنْ أَغْنِيَائِهِمْ، فَتُرَدُّ عَلَى فُقَرَائِهِمْ، فَإِنْ هُمْ طَاعُوا لَكَ بِذَلِكَ، فَإِيَّاكَ وَكَرَائِمَ أَمْوَالِهِمْ، وَاتَّقِ دَعْوَةَ الْمَظْلُومِ فَإِنَّهُ لَيْسَ بَيْنَهُ وَبَيْنَ اللَّهِ حِجَابٌ ‏"

Allah's Messenger (ﷺ) said to Mu`adh bin Jabal when he sent him to Yemen. "You will come to the people of Scripture, and when you reach them, invite them to testify that none has the right to be worshipped except Allah and that Muhammad is His Apostle. And if they obey you in that, then tell them that Allah has enjoined on them five prayers to be performed every day and night. And if they obey you in that, then tell them that Allah has enjoined on them Sadaqa (i.e. rak`at) to be taken from the rich amongst them and given to the poor amongst them. And if they obey you in that, then be cautious! Don't take their best properties (as Zakat) and be afraid of the curse of an oppressed person as there is no screen between his invocation and Allah.