Advice to Muadh b. Jabal; There is no barrier for the dua of oppressed

The Messenger of Allah ﷺ said to Muadh b. Jabal when he sent him to Yemen: “You will come to a people from the People of the Book. When you reach them, call them to testify that there is no deity except Allah and that Muhammad is the Messenger of Allah. If they obey you in that, then inform them that Allah has made obligatory upon them five prayers in every day and night.”

“If they obey you in that, then inform them that Allah has made obligatory upon them a charity to be taken from their rich and returned to their poor. If they obey you in that, then beware of taking the best of their wealth, and fear the dua of the oppressed, for there is no barrier between it and Allah.”

قَالَ رَسُولُ اللَّهِ ﷺ لِمُعَاذِ بْنِ جَبَلٍ، حِينَ بَعَثَهُ إِلَى الْيَمَنِ: «إِنَّكَ سَتَأْتِي قَوْمًا أَهْلَ كِتَابٍ، فَإِذَا جِئْتَهُمْ فَادْعُهُمْ إِلَى أَنْ يَشْهَدُوا أَنْ لَا إِلَهَ إِلَّا اللَّهُ، وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ. فَإِنْ هُمْ أَطَاعُوا لَكَ بِذَلِكَ، فَأَخْبِرْهُمْ أَنَّ اللَّهَ قَدْ فَرَضَ عَلَيْهِمْ خَمْسَ صَلَوَاتٍ فِي كُلِّ يَوْمٍ وَلَيْلَةٍ».

«فَإِنْ هُمْ أَطَاعُوا لَكَ بِذَلِكَ، فَأَخْبِرْهُمْ أَنَّ اللَّهَ قَدْ فَرَضَ عَلَيْهِمْ صَدَقَةً تُؤْخَذُ مِنْ أَغْنِيَائِهِمْ، فَتُرَدُّ عَلَى فُقَرَائِهِمْ. فَإِنْ هُمْ أَطَاعُوا لَكَ بِذَلِكَ، فَإِيَّاكَ وَكَرَائِمَ أَمْوَالِهِمْ، وَاتَّقِ دَعْوَةَ الْمَظْلُومِ، فَإِنَّهُ لَيْسَ بَيْنَهُ وَبَيْنَ اللَّهِ حِجَابٌ».