Sahih al-Bukhari 4305, 4306
Narrated Majashi:
I took my brother to the Prophet (ﷺ) after the Conquest (of Mecca) and said, "O Allah's Messenger (ﷺ)! I have 
come to you with my brother so that you may take a pledge of allegiance from him for migration." 
The Prophet (ﷺ) said, The people of migration (i.e. those who migrated to Medina before the Conquest) 
enjoyed the privileges of migration (i.e. there is no need for migration anymore)." I said to the 
Prophet, "For what will you take his pledge of allegiance?" The Prophet (ﷺ) said, "I will take his pledge of 
allegiance for Islam, Belief, and for Jihad (i.e. fighting in Allah's Cause).
حَدَّثَنَا عَمْرُو بْنُ خَالِدٍ، حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا عَاصِمٌ، عَنْ أَبِي عُثْمَانَ، قَالَ حَدَّثَنِي مُجَاشِعٌ، قَالَ أَتَيْتُ النَّبِيَّ صلى الله عليه وسلم بِأَخِي بَعْدَ الْفَتْحِ قُلْتُ يَا رَسُولَ اللَّهِ، جِئْتُكَ بِأَخِي لِتُبَايِعَهُ عَلَى الْهِجْرَةِ‏.‏ قَالَ ‏"‏ ذَهَبَ أَهْلُ الْهِجْرَةِ بِمَا فِيهَا ‏"‏‏.‏ فَقُلْتُ عَلَى أَىِّ شَىْءٍ تُبَايِعُهُ قَالَ ‏"‏ أُبَايِعُهُ عَلَى الإِسْلاَمِ وَالإِيمَانِ وَالْجِهَادِ‏" فَلَقِيتُ أَبَا مَعْبَدٍ بَعْدُ وَكَانَ أَكْبَرَهُمَا فَسَأَلْتُهُ فَقَالَ صَدَقَ مُجَاشِعٌ‏.