The Prophet ﷺ sent Mu'adh to Yemen.  

أَنَّ النَّبِيَّ ﷺ بَعَثَ مُعَاذًا إِلَى الْيَمَنِ  

When the Prophet ﷺ sent Muʿadh 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."  

سَمِعْتُ ابْنَ عَبَّاسٍ يَقُولُ لَمَّا بَعَثَ النَّبِيُّ ﷺ مُعَاذًا نَحْوَ الْيَمَنِ قَالَ لَهُ إِنَّكَ تَقْدَمُ عَلَى قَوْمٍ مِنْ أَهْلِ الْكِتَابِ فَلْيَكُنْ أَوَّلَ مَا تَدْعُوهُمْ إِلَى أَنْ يُوَحِّدُوا اللَّهَ تَعَالَى فَإِذَا عَرَفُوا ذَلِكَ فَأَخْبِرْهُمْ أَنَّ اللَّهَ فَرَضَ عَلَيْهِمْ خَمْسَ صَلَوَاتٍ فِي يَوْمِهِمْ وَلَيْلَتِهِمْ فَإِذَا صَلُّوا فَأَخْبِرْهُمْ أَنَّ اللَّهَ افْتَرَضَ عَلَيْهِمْ زَكَاةً فِي أَمْوَالِهِمْ تُؤْخَذُ مِنْ غَنِيِّهِمْ فَتُرَدُّ عَلَى فَقِيرِهِمْ فَإِذَا أَقَرُّوا بِذَلِكَ فَخُذْ مِنْهُمْ وَتَوَقَّ كَرَائِمَ أَمْوَالِ النَّاسِ  

The Prophet ﷺ said, "O Muʿadh! Do you know what Allah's Right upon His slaves is?" I said, "Allah and His Apostle know best." The Prophet ﷺ said, "To worship Him (Allah) Alone and to join none in worship with Him (Allah). Do you know what their right upon Him is?" I replied, "Allah and His Apostle know best." The Prophet ﷺ said, "Not to punish them (if they do so).  

قَالَ النَّبِيُّ ﷺ يَا مُعَاذُ أَتَدْرِي مَا حَقُّ اللَّهِ عَلَى الْعِبَادِ قَالَ اللَّهُ وَرَسُولُهُ أَعْلَمُ قَالَ أَنْ يَعْبُدُوهُ وَلاَ يُشْرِكُوا بِهِ شَيْئًا أَتَدْرِي مَا حَقُّهُمْ عَلَيْهِ قَالَ اللَّهُ وَرَسُولُهُ أَعْلَمُ قَالَ أَنْ لاَ يُعَذِّبَهُمْ  

A man heard another man reciting (in the prayers): 'Say (O Muhammad): "He is Allah, the One." (112.1) And he recited it repeatedly. When it was morning, he went to the Prophet ﷺ and informed him about that as if he considered that the recitation of that Sura by itself was not enough. Messenger of Allah ﷺ said, "By Him in Whose Hand my life is, it is equal to one-third of the Qur'an."  

سَمِعَ رَجُلاً يَقْرَأُ {قُلْ هُوَ اللَّهُ أَحَدٌ} يُرَدِّدُهَا فَلَمَّا أَصْبَحَ جَاءَ إِلَى النَّبِيِّ ﷺ فَذَكَرَ لَهُ ذَلِكَ وَكَأَنَّ الرَّجُلَ يَتَقَالُّهَا فَقَالَ رَسُولُ اللَّهِ ﷺ وَالَّذِي نَفْسِي بِيَدِهِ إِنَّهَا لَتَعْدِلُ ثُلُثَ الْقُرْآنِ زَادَ إِسْمَاعِيلُ بْنُ جَعْفَرٍ عَنْ مَالِكٍ عَنْ عَبْدِ الرَّحْمَنِ عَنْ أَبِيهِ عَنْ أَبِي سَعِيدٍ أَخْبَرَنِي أَخِي قَتَادَةُ بْنُ النُّعْمَانِ عَنِ النَّبِيِّ ﷺ  

The Prophet ﷺ sent (an army unit) under the command of a man who used to lead his companions in the prayers and would finish his recitation with (the Sura 112): 'Say (O Muhammad): "He is Allah, the One." ' (112.1) When they returned (from the battle), they mentioned that to the Prophet. He said (to them), "Ask him why he does so." They asked him and he said, "I do so because it mentions the qualities of the Beneficent and I love to recite it (in my prayer)." The Prophet; said (to them), "Tell him that Allah loves him."  

حَدَّثَهُ عَنْ أُمِّهِ عَمْرَةَ بِنْتِ عَبْدِ الرَّحْمَنِ وَكَانَتْ فِي حَجْرِ عَائِشَةَ زَوْجِ النَّبِيِّ ﷺ عَنْ عَائِشَةَ أَنَّ النَّبِيَّ ﷺ بَعَثَ رَجُلاً عَلَى سَرِيَّةٍ وَكَانَ يَقْرَأُ لأَصْحَابِهِ فِي صَلاَتِهِ فَيَخْتِمُ بِ {قُلْ هُوَ اللَّهُ أَحَدٌ} فَلَمَّا رَجَعُوا ذَكَرُوا ذَلِكَ لِلنَّبِيِّ ﷺ فَقَالَ سَلُوهُ لأَىِّ شَىْءٍ يَصْنَعُ ذَلِكَ فَسَأَلُوهُ فَقَالَ لأَنَّهَا صِفَةُ الرَّحْمَنِ وَأَنَا أُحِبُّ أَنْ أَقْرَأَ بِهَا فَقَالَ النَّبِيُّ ﷺ أَخْبِرُوهُ أَنَّ اللَّهَ يُحِبُّهُ