Narrated 'Aisha:

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 Surah al-Ikhlaas): '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 ﷺ said (to them), "Tell him that Allah loves him"

حَدَّثَنَا أَحْمَدُ بْنُ صَالِحٍ، حَدَّثَنَا ابْنُ وَهْبٍ، حَدَّثَنَا عَمْرٌو، عَنِ ابْنِ أَبِي هِلاَلٍ، أَنَّ أَبَا الرِّجَالِ، مُحَمَّدَ بْنَ عَبْدِ الرَّحْمَنِ 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 ـ {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 ".