وَآخَرِينَ مِنْهُمْ لَمَّا يَلْحَقُوا بِهِمْ وَهُوَ الْعَزِيزُ الْحَكِيمُ (...And [ this Messenger is sent also ] to others of them who did not join them so far. And He is the All-mighty, the All-wise...62:3) The word 'akharin means 'other people' and the phrase لَمَّا يَلْحَقُوا بِهِمْ means 'those people who have not yet joined the unlettered people'. This refers to all those Muslims who will enter the fold of Islam until the Last Hour [ as transmitted by Ibn Zaid, Mujahid and others ]. This indicates that the succeeding generations of Muslims will be appended to the earlier generations of believers, that is, the noble Companions. This is great good news for the succeeding generations of Muslims. [ Ruh ].
Grammatically, there are two views regarding the conjoining of the word 'akharin. One view holds that it is conjoined to ummiyyin and it means that 'Allah has sent His Messenger ﷺ among the unlettered people and also among those who have not yet joined them'. Sending the Prophet ﷺ among the present unlettered people is quite obvious, but 'sending him among those who have not yet come' needs explanation. Bayan-ul-Qur'an explains that 'sending among them' stands for 'sending for them' because the preposition fi in Arabic is also used in the sense of 'for'. According to some other grammarians, however, the word 'akharin is conjoined to the objective pronoun him attached to the verb yu'allimu-hum, in which case the interpretation would be 'the Prophet ﷺ teaches the unlettered people and also the people who have not joined them so far'. [ Mazhari prefers the latter interpretation ].
Sayyidna Abu Hurairah رضی اللہ تعالیٰ عنہ narrates, as recorded in Bukhari and Muslim, that they were sitting in the company of the Holy Prophet ﷺ when Surah Al-Jumu'ah was revealed. He recited it to them, and when he reached the verse وَآخَرِينَ مِنْهُمْ لَمَّا يَلْحَقُوا بِهِمْ (...and others of them who have not joined them so far...62:3) they asked him who are these 'others'. He remained silent. They asked him the second time and he remained silent. They asked him the third time, and he put his blessed hand on the back of Sayyidna Salman Al-Farisi ؓ [ who was at that time in the gathering ] and said: "If faith were on Pleiades, even then some men or a man from these people would attain it." [ Mazhari ]. This narration does not specify people of Persia, but it does prove that they are included in the general sense of 'others'. This narration speaks greatly of all non-Arabs who embrace Islam. [ Mazhari ].