Q 24:62

The believers are only those who believe in Allah and His Messenger; and when they are with him on some common matter, they go not away until they have asked his permission. Verily, those who ask your permission, those are they who (really) believe in Allah and His Messenger. So if they ask your permission for some affairs of theirs, give permission to whom you will of them, and ask Allah for their forgiveness. Truly, Allah is Oft-Forgiving, Most Merciful (62) Asking Permission to Leave When They Are Doing Something Together This is another matter of etiquette to which Allah has guided His believing servants. Just as He commanded them to seek permission when entering, He also commanded them to seek permission when leaving, especially when they are doing something together with the Messenger ﷺ, such as the Friday, 'Id, or congregational prayers, or a meeting for the purpose of consultation and so on. Allah commanded them not to leave him in these situations until they had asked his permission. If they did this, then they were of the true believers. Then Allah commanded His Messenger ﷺ to give permission when someone asked for it, if he wanted to. He said: فَأْذَن لِّمَن شِئْتَ مِنْهُمْ وَاسْتَغْفِرْ لَهُمُ اللَّهَ (give permission to whom you will of them, and ask Allah for their forgiveness.)Abu Dawud reported that Abu Hurayrah said, "The Messenger of Allah ﷺ said: إِذَا انْتَهَى أَحَدُكُمْ إِلَى الْمَجْلِسِ فَلْيُسَلِّمْ، فَإِذَا أَرَادَ أَنْ يَقُومَ فَلْيُسَلِّمْ، فَلَيْسَتِ الْأُولَى بِأَحَقَّ مِنَ الْآخِرَةِ (When any of you joins a gathering, let him say Salam, and when he wants to leave, let him say Salam. The former is not more important than the latter.) This was also recorded by At-Tirmidhi and An-Nasa'i; At-Tirmidhi said: "It is a Hasan Hadith."