Asalamu Alykum
Brother Wanderer, I have to say that this term brings up much memories of ways how Allah(swt) has guided me Subhan Allah.
An answer to your question maybe found in this excerpt by brother Joseph. Insha'Allah this helps
(4) PROPHETHOOD HAS ENDED. THERE ARE NO MORE DIVINE SCRIPTURES
033.040
"Muhammad is not the father of any of your men, but (he is) the Messenger of God, and the seal of the Prophets (Arabic: Khatama Nabiyina): and God has full knowledge of all things"
Please note the word 'Khaatam(a)' which in Arabic signifies a seal, or more accurately, an object used to seal or to put an impression of a signet on a writing or book. This endows it with a covering, an act of securing and implies the reaching of an end. This term's usage is even more significant when understood in the light of Prophet Muhammad's (pbuh) ministry which was to deliver the final message of God. Here the relationship of a signet or stamp to impress on a book to imply the ending of such a message cannot simply be overlooked.
It is in this capacity as a 'Nabi' (one through whom a scripture is revealed), that this seal has been set. Therefore, by acting as a seal to Prophethood, this also negates the possibility of any new Divine scriptures.
[1]I hope you don't mind me sharing on this post a story that I remember which brought me to understand this term much better Alhamdulila.
A few years ago before I was introduced to this site, I was told by my father to watch out and not give in about all the hadith that I hear. He simply and quickly just told me be careful some hadith is not true.
In my mind, I was like wow, really all these years and now you tell me. So later on I started to search for the real authentic hadith. I wanted to figure out a way how to tell between the right ones and the fake ones. So it seemed as my only answer was to go back to every single hadith and try to figure it out. So I thought ok the best thing to do is start with the earliest narrations about the prophet Muhammad(pbuh). I become quite frustrated to learn that some of the oldest books by scholars were only written in the Arabic language, and I had no idea how to read or write Arabic. I said to myself that this is going to be a long journey, and I dont know how I would learn Arabic at the moment efficiently. As my search started about hadith I came to realize Alhamdulila that some hadith like about the mahdi and the dajjal may of been fake due to the fact there was nothing mentioned in the Quran. I had taken all this news pretty seriously and was pretty shaken.
I can’t remember exactly what happened after, but I was somehow searching for a solid meaning about verse 3:81. I wanted to know who the “messenger” being spoken about in that verse was.
I looked online, read many opinions, some argued it was mahdi, some argued it was prophet Muhammad etc, but I couldn’t be convinced with any of the opinions. They all had some loop holes.
I then somehow read a long long article which seemed like it was going to give a good answer about verse 3:81. The article was so interesting that I couldn’t stop reading it.
It was an article about how a new prophet will come to every nation and every prophet will come in the language of its nation. That every so many years a prophet will come with new laws as the old laws are outdated. That the world is progressing and the world needs a new Book with new laws. I was shocked. It made sense. It only used verses from the Quran. I honestly remember that I couldn’t sleep for days.
I realized after that this author was somehow advocating the Bahai faith. As I read bits and pieces, it seemed like laws of marriage were reduced for example instead of the assumed 4 wives, to 2 wives, the punishments were lifted, etc as the aim was that the world is undergoing changes.
As of that time I was still under the impression that Islam was still a religion which sourced from the Quran and the hadith. I was just assured that some hadith were fabricated and the ones authentic were needed to complete the religion some how.
I was trying to verify the verses that the author was using. Alhamdulila I then realized that the author was using the terms “prophet” and “messengers” interchangeably.
The term that really was very challenging to figure out was “Khatama-Nabiyyina”. The article actually used this verse as well but gave the definition that it was a stamp or mark. I tried to look for definitions but most of what I saw was that it meant a “stamp”, “mark” of some sort, like a birth mark. That the prophet Muhammad has a mark on his shoulder to indicate and authenticate he was a prophet of God.
The traditional view was that “messengers” had more superiority and authority than “prophets”. Since there was no where in the Quran that said Muhammad was the seal of the messengers, so I knew then that I cannot figure it out through defining messengership.
I had to figure out what the term “Khatama-Nabiyyina”. It was either the article was correct and prophethood continues and the “Khatam” means a sort of ring,symbol, stamp, mark , etc that a prophet has to show his authenticity.
Or the other meaning would be a seal ending all prophethood, which from a traditional point of view still wouldn’t of made sense in my mind back then since the traditional view holds messengers of greater authority and no where in the Quran does it mention the seal of all messengers, only the seal of the prophets.
Alhamdulila I can't forget the time I came stumbling across this website. I felt as if a huge burden came off my back in so many ways. Masha'Allah I was first amazed how verse 3:81 was explained. This lead me to other related articles which then reduced my searching from a plethora of books to just the Quran Alhamdulila. I’ve came to learn that God may guide anyone in any language. It was just a new view of the world that had brightened up Thank God. ( I have to thank my Generous Creator greatly, if it was not for Him I would surely have been misguided and may He grant blessing and mercy on Joseph, his family and all those who are part of this website and reward them tremendously).
The terms messengers and prophets have been explained in great detail on this website by brother Joseph. I came to realize that God has taught people and those people maybe used as a tool to spread the message. Call them warners, messengers, helpers, spreaders of good tidings, etc. But the prophethood has been sealed. It has been sourced out from dictionaries and goes consistent with the message of the Quran.
Another reason to support that no other books are to come as revelations would be, these verses below:
7:185 "Do they see nothing in the government of the heavens and the earth and all that God has created? (Do they not see) that it may well be that their terms are drawing to an end? In what narrative (Hadith) after this will they then believe?"
77:50 "Then In what narrative (Hadithin), after this will they believe?"
[1] END OF PROPHETHOOD - CONTINUATION OF MESSENGERS?
http://quransmessage.com/articles/end%20of%20prophethood%20FM3.htm