8:72
إِنَّ ٱلَّذِينَ ءَامَنُوا۟ وَهَاجَرُوا۟ وَجَٰهَدُوا۟ بِأَمْوَٰلِهِمْ وَأَنفُسِهِمْ فِى سَبِيلِ ٱللَّهِ وَٱلَّذِينَ ءَاوَوا۟ وَّنَصَرُوٓا۟ أُو۟لَٰٓئِكَ بَعْضُهُمْ أَوْلِيَآءُ بَعْضٍۢ ۚ وَٱلَّذِينَ ءَامَنُوا۟ وَلَمْ يُهَاجِرُوا۟ مَا لَكُم مِّن وَلَٰيَتِهِم مِّن شَىْءٍ حَتَّىٰ يُهَاجِرُوا۟ ۚ وَإِنِ ٱسْتَنصَرُوكُمْ فِى ٱلدِّينِ فَعَلَيْكُمُ ٱلنَّصْرُ إِلَّا عَلَىٰ قَوْمٍۭ بَيْنَكُمْ وَبَيْنَهُم مِّيثَٰقٌۭ ۗ وَٱللَّهُ بِمَا تَعْمَلُونَ بَصِيرٌۭ
Indeed, those who have believed and emigrated and fought with their wealth and lives in the cause of Allah and those who gave shelter and aided - they are allies of one another. But those who believed and did not emigrate - for you there is no guardianship of them until they emigrate. And if they seek help of you for the religion, then you must help, except against a people between yourselves and whom is a treaty. And Allah is Seeing of what you do.
Translation · Saheeh International
Tafsir
Ibn Kathīr (abridged)
The Muhajirin and Al-Ansar are the Supporters of One Another
Here Allah mentions the types of believers, dividing them into the Muhajirin, who left their homes and estates, emigrating to give support to Allah and His Messenger to establish His religion. They gave up their wealth and themselves in this cause. There are also the Ansar, the Muslims of Al-Madinah, who gave asylum to their Muhajirin brethren in their own homes and comforted them with their wealth. They also gave aid to Allah and His Messenger by fighting alongside the Muhajirun. Certainly they are,
بَعْضُهُمْ أَوْلِيَآءُ بَعْضٍ
(allies to one another), for each one of them has more right to the other than anyone else. This is why Allah's Messenger ﷺ forged ties of brotherhood between the Muhajirin and Ansar, as Al-Bukhari recorded from Ibn `Abbas. They used to inherit from each other, having more right to inheritance than the deceased man's relatives, until Allah abrogated that practice with the fixed share for near relatives. Imam Ahmad recorded that Jarir bin `Abdullah Al-Bajali said that the Messenger of Allah ﷺ said,
«الْمُهَاجِرُون وَالْأَنْصَارُ أَوْلِيَاءُ بَعْضُهُمْ لِبَعْضٍ، وَالطُّلَقَاءُ مِنْ قُرَيْشٍ، وَالْعُتَقَاءُ مِنْ ثَقِيفٍ بَعْضُهُمْ أَوْلِيَاءُ بَعْضٍ إِلَى يَوْمِ الْقِيَامَة»
(The Muhajirun and Al-Ansar are the supporters of each other, while the Tulaqa' of Quraysh (whom the Prophet set free after conquering Makkah) and `Utaqa' from Thaqif (whom the Prophet set free from captivity after the battle of Hunayn) are supporters of each other until the Day of Resurrection. )