Hadith: One will be with those whom he loves

عن أبي موسى الأشعري رضي الله عنه مرفوعاً: « المَرْءُ مَعَ مَنْ أَحَبَّ ». وفي رواية: قِيلَ لِلنبي صلى الله عليه وسلم : الرَّجُلُ يُحِبُّ القَوْمَ وَلَمَّا يَلْحَق بهم؟ قال: « المَرْءُ مَعَ مَنْ أَحَبَّ». عن عبد الله بن مسعود رضي الله عنه قال: جاء رجل إلى رسول الله صلى الله عليه وسلم فقال: يا رسول الله، كَيفَ تَقُولُ فِي رَجُلٍ أحَبَّ قَومًا ولم يَلحَق بِهم؟ فقال رسول الله صلى الله عليه وسلم : «المَرْءُ مَعَ مَنْ أَحَبَّ».
[صحيحان] - [الحديث الأول: متفق عليه. الحديث الثاني: متفق عليه]

Abu Mūsa al-Ash‘ari (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "One will be with those whom he loves." Another narration reads: "It was said to the Prophet (may Allah's peace and blessings be upon him): 'What about a man who loves some people but he cannot be as good as them?' He said: 'One will be with those whom he loves.'" ‘Abdullāh ibn Mas‘ūd (may Allah be pleased with him) reported: A man came to the Messenger of Allah (may Allah's peace and blessings be upon him) and said: 'O Messenger of Allah, what do you say about a man who loves some people but cannot catch up with their good deeds?' The Messenger of Allah (may Allah's peace and blessings be upon him) said: 'One will be with those whom he loves.’"
[Sahih/Authentic with its two versions] - [Al-Bukhari and Muslim with its two versions]

Explanation

In the Hereafter, one will be with those whom he used to love in the worldly life. This Hadīth encourages having strong love for the messengers of Allah, the righteous people, and their followers according to their ranks. It also warns against loving those who oppose them. Love is a proof of one's strong relationship and connection with the one whom he loves, his agreement with his morals, and following his example. It is a proof of these things and leads to them as well. Also, whoever loves Allah, the Almighty, that very love is something that brings one closer to Him. Indeed, Allah is the Most Appreciative. He grants the one seeking His closeness a multiplied amount of what one exerts. Being with those whom one loves does not necessarily mean being equal in status or position. That differs according to one's good deeds and profitable actions. Being "with" them occurs by their mere sharing in something, not necessarily everything. If it happens that all enter Paradise, then they are all with each other, even if the degrees vary. So, whoever loves the Messenger (may Allah’s peace and blessings be upon him) or one of the believers, then he will be with him in Paradise by his good intention, because it is the fundamental element, and actions are subordinate to it. It is not necessarily understood that being with someone means occupying the same degree as his, or receiving the same reward as his from all aspects.