All the Prophets are His followers
Almighty Allah says in the Holy Quran:
And, ( O Beloved, recall the time) when Allah took a firm covenant from the Prophets: ‘When I give you the Book and Wisdom and then there comes to you the Messenger (who is exalted in glory above all and) who shall validate the Books you will have with you, you shall then, most certainly, believe in him and most surely help him.’ Allah said: ‘Do you affirm, and on this (condition) hold fast to My heavy Covenant?’ All submitted: ‘We affirm.’ Allah said: ‘Bear witness then and I am also with you among the witnesses.’ Surah Aale Imran (3:81)
This shows that all other Prophets are the followers of the Holy Prophet (Sallallahu alaihi wa sallam). For this reason, on the Day of Judgment all the Prophets will be under the flag of the Holy Prophet (Sallallahu alaihi wa sallam).
The greatness of the Holy Prophet (Sallallahu alaihi wa sallam) was shown in the night of the Ascension (Meraj). The Holy Prophet (Sallallahu alaihi wa sallam) was made the Imam of the Salaat and all other Prophets offered Salaat in His lead.
If all Prophets are His followers, then what doubt is there in their followers being His followers? For this reason, the Holy Prophet (Sallallahu alaihi wa sallam) said: I have been sent to all humankind.
Allah Most High says:
And We have not sent you but as a Bearer of the glad tidings and as a Warner to the entire mankind…Surah Saba (34:28)
Moosa (May peace be upon him) was also virtually in the Ummah of the Holy Prophet (Sallallahu alaihi wa sallam), but when he learnt the excellence of the actual Ummah of the Holy Prophet (Sallallahu alaihi wa sallam), he supplicated that he should be included in the actual Ummah of the Holy Prophet (Sallallahu alaihi wa sallam).
To be continued…
[Excerpted from Maqasid Ul Islam, Vol. 1]