Verses refer to the concept of Aʿraf (a place between Heaven and Hell) and those who are in Aʿraf.
Aʿraf is the fortress that separates The Garden of Paradise from The Fire of Hell.
On the Judgement Day, the masses will come toward Aʿraf, none of whom knowing whether they are destined to paradise, or hell.
But there will be some people, standing on Aʿraf, who will be recognizing some faces among the crowd and bestowing upon them with salute, while recognizing some others and condemning on them and asking God not to join them with them (literally witnessing).
In accordance with the definition of these people, the verse 22:78 mentions that if the believers strive as they should do, the Messenger will be a witness to them, and they will be witnesses for the mankind.
So it is likely that who is meant by that are certain selected people from among the crowd, like messengers, prophets, apostles, those whom had followed them and striven/died/been killed in the right cause of God, and those whom were bestowed upon with Paradise when they were alive, whom are given the right to witness on the rest of the mankind.
- And if the people of the towns had believed and guarded (against evil) We would certainly have opened up for them blessings from the heaven and the earth, but they rejected, so We overtook them for what they had earned.
- This verse is quoted in the Shi'a view of Fatimah's last public speech.
- Al Aaraaf