Question Summary:
Duaa to be recited at the conclusion of a gathering

Question Detail:

1. Kindly provide me with evidenced reference regarding reciting "Subhaanarabbika rabbil Izzati Amma Yassifoon Wassalaamun Alal Mursaleen Walhumdulillahir Rabbil Aalameen" at the conclusion of an action.
And some people also recite Suratul 'Asr. Need clarification please

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
The following is the Hadith referred to in the query:
 
حَدَّثَنَا هُشَيْمٌ، عَنْ أَبِي هَارُونَ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ: سَمِعْتُ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ غَيْرَ مَرَّةٍ يَقُولُ فِي آخِرِ صَلَاتِهِ عِنْدَ انْصِرَافِهِ: سُبْحَانَ رَبِّكَ رَبِّ الْعِزَّةِ عَمَّا يَصِفُونَ، وَسَلَامٌ عَلَى الْمُرْسَلَينَ، وَالْحَمْدُ لِلَّهِ رَبِّ الْعَالَمِينَ مصنف ابن أبي شيبة (3097)
 
Hazrat Abu Saeed Khudri (radiallahu anhu) is reported to have said: “I have heard it many times from the Holy Prophet (sallallahu alayhi wasallam) that after the Salah was over, He used to recite these verses: “Glorified be you, Lord of Majesty above what they describe! And peace be upon the Messenger and all praise belongs to Allah, the Lord of the worlds” (Musannaf ibn Abi Shaybah: 3097) 
وَقَدْ رُوِيَ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ كَانَ يَقُولُ بَعْدَ التَّسْلِيمِ: «لَا إِلَهَ إِلَّا اللَّهُ وَحْدَهُ لَا شَرِيكَ لَهُ، لَهُ المُلْكُ وَلَهُ الحَمْدُ، يُحْيِي وَيُمِيتُ، وَهُوَ عَلَى كُلِّ شَيْءٍ قَدِيرٌ، اللَّهُمَّ لَا مَانِعَ لِمَا أَعْطَيْتَ، وَلَا مُعْطِيَ لِمَا مَنَعْتَ، وَلَا يَنْفَعُ ذَا الجَدِّ مِنْكَ الجَدُّ» وَرُوِيَ أَنَّهُ كَانَ يَقُولُ: «سُبْحَانَ رَبِّكَ رَبِّ العِزَّةِ عَمَّا يَصِفُونَ، وَسَلَامٌ عَلَى المُرْسَلِينَ وَالحَمْدُ لِلَّهِ رَبِّ العَالَمِينَ سنن الترمذي ت شاكر (299)          
A similar version from the same sanad is reported by sanad from a Marwan ibn Mu'awiyah and Abu Mu'awiyah who from Asim Ahwal, saying: (You are blessed O Owner of Glory and Honour) There is no God but Allah Alone. He has no partner. To Him belongs the Kingdom and for Him is all praise. He gives life and causes death. And, He is over all things Capable. 0 Allah, no one can deny what you grant and no one can give what you deny. And the effort of one who makes effort cannot help him against You He would also say: Glorified be you, Lord of Majesty above what they describe! And peace be upon the Messenger and all praise belongs to Allah, the Lord of the worlds. These are verses of the Quran 37: 180.182 (Tirmizi: 299) 
Furthermore, it is narrated from Hazrat Ali (radiallahu anhu): “Whoever wishes to have the best of return filled to the brim on the day of Judgement should recite this verse at the end of every sitting.[1]
عَنْ عَلِيٍّ، قَالَ: " مَنْ أَحَبَّ أَنْ يَكْتَالَ، بِالْمِكْيَالِ الْأَوْفَى فَلْيَقْرَأْ آخِرَ مَجْلِسِهِ، أَوْ حِينَ يَقُومُ: {سُبْحَانَ رَبِّكَ رَبِّ الْعِزَّةِ عَمَّا يَصِفُونَ وَسَلَامٌ عَلَى الْمُرْسَلِينَ وَالْحَمْدُ لِلهِ رَبِّ الْعَالَمِينَ} [الصافات: 181] حلية الأولياء وطبقات الأصفياء (123/7) دار الكتاب العربي-بيروت        
It is clearly understood from the above mentioned Ahaadith that our Beloved Nabi (alayhissalam) used to recite the last verse of Surah Assaaffat at the completion of Salah, and he (sallallahu alayhi wasallam) further emphasised reading it after every gathering/sitting.
With regard to reciting Surah Al-‘Asr; there is a narration which indicates that it was the practice of Sahaba (radiallahu anhum) that they would recite it before leaving a gathering. Consider the following narration:
قال الطبراني: حدثنا محمد بن هشام المشتملى، حدثنا عبيد الله بن أبى عائشة، حدثنا حماد، عن ثابت، عن أبى مدينة الدارمي ـ وكانت له صحبة ـ قال: كان الرَّجُلاَنِ من أصحاب رسول الله -صلى الله عليه وسلم -إذا التقيا/ لم يتفرقا حتى يقرأ أحدهما على الآخر سورة {والْعَصْرِ} إلى آخرها، ثم يسلم أحدهما على الآخر. جامع المسانيد والسنن (6272)
 
It was narrated that Abu Madinah Al-Darimi said: When two men among the companions of the Prophet (sallallahu alayhi wasallam) met, they did not part until one of them recited to the other Surah Al-‘Asr, then one would say salaam to (greet) the other.[2]
 
 
And Allah Ta’āla Knows Best
Asim Patel
Student Darul Iftaa
Venda, South Africa
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net