Tafsir of Al-Hujurat 49:10

This is a confirmation of the obligation placed upon those who undertake reconciliation between believers who have fallen into discord. It is a clarification that faith has established between its people a bond of kinship and a close lineage—one that, if it does not surpass biological brotherhood, certainly does not fall short of it or fail to reach its ultimate goal.

It is the custom of people that when such discord arises between two biological brothers, others must rise to resolve and remove it. They must exert every effort—difficult or easy—to walk toward reconciliation and send intermediaries between them, until they find someone to mend the rift in their harmony and restore the moisture to their dried-up connection. Brotherhood in religion is more deserving of this, and even more intense efforts.

The Prophet (ﷺ) said: "A Muslim is the brother of a Muslim; he does not wrong him, nor abandon him, nor insult him, nor build higher than him to block his wind without his permission, nor harm him with the scent of his cooking pot." Then he said: "Take heed, though few among you will take heed."

If you ask: Why were two mentioned specifically, rather than a group? I say: Because the minimum number between whom discord can occur is two. If reconciliation is mandatory between the fewest, it is even more mandatory between the many, because the corruption in the discord of a group is greater than that of two. It is also said that the "two brothers" refers to the Aws and the Khazraj. It has been recited as "between your brothers" (ikhwatikum and ikhwanikum).

The meaning is: The believers are nothing but brothers, purely and exclusively so. The suspicions of being strangers have been removed from them, and the delicacy of their state in blending and unity forbids them from engaging in anything that results in severing ties. Therefore, hasten to cut off such discord if it occurs, and eradicate it.

{And fear Allah}: For if you do so, piety will compel you toward connection, harmony, and rushing to remove whatever excess occurs. Your doing so makes the arrival of Allah’s mercy to you and the encompassing of His compassion upon you worthy of your hope.