The Messenger of Allah ﷺ sent a man on a campaign, and he used to recite to his companions when leading them in prayer, and would conclude with 'Say: He is Allah, (the) One.' When they returned, they told the Messenger of Allah ﷺ about that. He said: "Ask them why he did that." So they asked him and he said: "Because it is a description of the Most Merciful, the Mighty and Sublime, and I love to recite it." The Messenger of Allah ﷺ said: "Tell him that Allah (SWT), the Mighty and Sublime, loves him."  

أَنَّ رَسُولَ اللَّهِ ﷺ بَعَثَ رَجُلاً عَلَى سَرِيَّةٍ فَكَانَ يَقْرَأُ لأَصْحَابِهِ فِي صَلاَتِهِمْ فَيَخْتِمُ بِ { قُلْ هُوَ اللَّهُ أَحَدٌ } فَلَمَّا رَجَعُوا ذَكَرُوا ذَلِكَ لِرَسُولِ اللَّهِ ﷺ فَقَالَ سَلُوهُ لأَىِّ شَىْءٍ فَعَلَ ذَلِكَ فَسَأَلُوهُ فَقَالَ لأَنَّهَا صِفَةُ الرَّحْمَنِ ﷻ فَأَنَا أُحِبُّ أَنْ أَقْرَأَ بِهَا قَالَ رَسُولُ اللَّهِ ﷺ أَخْبِرُوهُ أَنَّ اللَّهَ ﷻ يُحِبُّهُ  

"I heard Abu Hurairah say: 'I came back (from a journey) with the Messenger of Allah ﷺ and he heard a man reciting 'Say: He is Allah, (the) One, Allah-us-Samad (the Self-Sufficient Master). He begets not, nor was He begotten. And there is none equal or comparable unto Him.' The Messenger of Allah ﷺ said: 'It is guaranteed.' We asked him: 'What, O Messenger of Allah?' He said: 'Paradise.'"  

سَمِعْتُ أَبَا هُرَيْرَةَ يَقُولُ أَقْبَلْتُ مَعَ رَسُولِ اللَّهِ ﷺ فَسَمِعَ رَجُلاً يَقْرَأُ { قُلْ هُوَ اللَّهُ أَحَدٌ * اللَّهُ الصَّمَدُ * لَمْ يَلِدْ وَلَمْ يُولَدْ * وَلَمْ يَكُنْ لَهُ كُفُوًا أَحَدٌ } فَقَالَ رَسُولُ اللَّهِ ﷺ وَجَبَتْ فَسَأَلْتُهُ مَاذَا يَا رَسُولَ اللَّهِ قَالَ الْجَنَّةُ  

A man heard another man reciting "Say: He is Allah, (the) One" and repeating it. When morning came he went to the Messenger of Allah ﷺ and told him about that. The Messenger of Allah ﷺ said: "By the One in Whose Hand is my soul, it is equal to one-third of the Quran."  

سَمِعَ رَجُلاً يَقْرَأُ { قُلْ هُوَ اللَّهُ أَحَدٌ } يُرَدِّدُهَا فَلَمَّا أَصْبَحَ جَاءَ إِلَى النَّبِيِّ ﷺ فَذَكَرَ ذَلِكَ لَهُ فَقَالَ رَسُولُ اللَّهِ ﷺ وَالَّذِي نَفْسِي بِيَدِهِ إِنَّهَا لَتَعْدِلُ ثُلُثَ الْقُرْآنِ  

The Prophet ﷺ said: "Say: He is Allah, (the) One" is one-third of the Quran."  

عَنِ النَّبِيِّ ﷺ قَالَ { قُلْ هُوَ اللَّهُ أَحَدٌ } ثُلُثُ الْقُرْآنِ قَالَ أَبُو عَبْدِ الرَّحْمَنِ مَا أَعْرِفُ إِسْنَادًا أَطْوَلَ مِنْ هَذَا