The Prophet ﷺ said: When a man loves his brother, he should tell him that he loves him.  

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا أَحَبَّ الرَّجُلُ أَخَاهُ فَلْيُخْبِرْهُ أَنَّهُ يُحِبُّهُ  

A man was with the Prophet ﷺ and a man passed by him and said: Messenger of Allah! I love this man. The Messenger of Allah ﷺ then asked: Have you informed him? He replied: No. He said: Inform him. He then went to him and said: I love you for Allah's sake. He replied: May He for Whose sake you love me love you!  

أَنَّ رَجُلاً كَانَ عِنْدَ النَّبِيِّ ﷺ فَمَرَّ بِهِ رَجُلٌ فَقَالَ يَا رَسُولَ اللَّهِ إِنِّي لأُحِبُّ هَذَا فَقَالَ لَهُ النَّبِيُّ ﷺ أَعْلَمْتَهُ قَالَ لاَ قَالَ أَعْلِمْهُ قَالَ فَلَحِقَهُ فَقَالَ إِنِّي أُحِبُّكَ فِي اللَّهِ فَقَالَ أَحَبَّكَ الَّذِي أَحْبَبْتَنِي لَهُ  

Messenger of Allah! A man loves some people, but he cannot do work like their work. He replied; Yes, Abu Dharr, will be with those whom you love. Abu Dharr then repeated it. The Messenger of Allah (May peace be upon him) also repeated it.  

أَنَّهُ قَالَ يَا رَسُولَ اللَّهِ الرَّجُلُ يُحِبُّ الْقَوْمَ وَلاَ يَسْتَطِيعُ أَنْ يَعْمَلَ كَعَمَلِهِمْ قَالَ أَنْتَ يَا أَبَا ذَرٍّ مَعَ مَنْ أَحْبَبْتَ قَالَ فَإِنِّي أُحِبُّ اللَّهَ وَرَسُولَهُ قَالَ فَإِنَّكَ مَعَ مَنْ أَحْبَبْتَ قَالَ فَأَعَادَهَا أَبُو ذَرٍّ فَأَعَادَهَا رَسُولُ اللَّهِ ﷺ  

I never saw the Companions of the Messenger of Allah (May peace be upon him) so happy about anything as I saw them happy about this thing. A man said : Messenger of Allah! A man loves another man for the good work which he does, but he himself cannot do like it. The Messenger of Allah (May peace be upon him) said: A man will be with those whom he loves.  

رَأَيْتُ أَصْحَابَ رَسُولِ اللَّهِ ﷺ فَرِحُوا بِشَىْءٍ لَمْ أَرَهُمْ فَرِحُوا بِشَىْءٍ أَشَدَّ مِنْهُ قَالَ رَجُلٌ يَا رَسُولَ اللَّهِ الرَّجُلُ يُحِبُّ الرَّجُلَ عَلَى الْعَمَلِ مِنَ الْخَيْرِ يَعْمَلُ بِهِ وَلاَ يَعْمَلُ بِمِثْلِهِ فَقَالَ رَسُولُ اللَّهِ ﷺ الْمَرْءُ مَعَ مَنْ أَحَبَّ