Assalamu ‘Alaikum Warahmat Allah Wabarakatuh,
I am going to add some responses concerning the Finality of Prophethood. As this subject is a very sensitive one to all, and requires deep understanding, I am going to take a quite different approach. I will break down the argument and present it in various parts so that the concept is understood bit by bit. As always, anyone wishing to understand this subject is best served by the explanation of the Imam al-Mahdi (‘alayhi al-salam) himself in his book ”A Misconception Removed.”
[The author of this post is attempting to show how the word khatam is understood when it is pre-fixed to any group (i.e., Seal of the writers / poets, etc.)]
1. خاتم النبین as the best of the Prophets and as the prophet who has the perfect qualities of the Prophethood
When ever خاتم is used for the group of a people (مرکب اضافی کے طور پر)، then it is necessary that the person who is entitled with the term خاتم becomes best of that group .
It is because; you cannot produce the impression of something over the other, until that thing has perfectly and flawlessly acquired all the characteristics of that thing in it. When it has the perfect pattern (engraving, marking, impression) of something. then and only then that thing will be able to produce the impression perfectly in other things.
Similarly when a person becomes a خاتم of some group , then he must acquire all the qualities of that group fully and perfectly .
خاتم الاولیا , will be a person who have attained the quality of the ولایت perfectly in himself, then and only then he will be able to produce this quality in the other persons , thus meaning of خاتم in the term خاتم الاولیا , necessarily requires that خاتم الاولیا is the best of the all اولیا.
خاتم المفسرین , will be that who has fully and perfectly acquired the property of the group of مفسرین. Then and only then he will be able to transmit his knowledge and makes his students to become like him.
خاتم الشعرا, will be a person who have perfected himself in making poetic verses and have attained that quality fully in himself , then and only then he will be able to produce other poets .
This suggests that when the term خاتم النبین is used, then prophet hazrat Muhammad (saw) cannot become a خاتم النبین , until he (saw) has attained all the qualities of the prophethood(نبوت) perfectly, completely and absolutely in himself (saw). And as hazrat Muhammad (saw) is the most perfect prophets and all the qualities of the prophethood in him (saw) and each quality have reached to its zenith, in the pious and glorious personality of the hazrat Muhammad (saw). That is why , hazrat Muhammad (saw) is the best and superior to all the other prophets.
Our above discussion is to show that خاتم, when used as the مضاف in مرکب اضافی, then it will definitely have the meaning of
Best of that group. That is the reason you will find so many usage of the خاتم for a group of people in the meaning of BEST.
The usage of خاتم in the meaning of the BEST is the logically outcome of the fundamental meanings of the word خاتم , that is producing the impression of something on the something else. It is not listed in the dictionary meanings of the word خاتم but it will be a necessary consequence of the usage of the خاتم when it is used as the مضاف for a group as a مرکب اضافی
Hence first associated meanings of the term khataMunabeen (خاتم النبین)are the best of the prophets
Source: Ehsan Ahmad, Rah-e-Huda Forum