Dear submitmj, in the absence of hadees, how would you prove that Prophet of Islam really is the last prophet?
It can be proven very easily.
1) The Quran states it very clearly in Sura 33, verse 40.33:40] Muhammad was not the father of any man among you. He was a messenger of GOD and the final prophet. GOD is fully aware of all things.
The arabic is very clear, 'rasoolallah wa Khaatimun Nabiyeen' (messenger and final prophet).
Rasool = messenger
Allah = GOD
wa = and
Khaatimun = final
Nabiyeen = prophet
2) The math miracle of 19 as decreed in Sura 74:30-35 proves every single sura, verse, word and letter is the unaltered word of GOD. So, when you know for certain the Quran is the complete and fully detailed Word of GOD, you know what GOD says in it is the absolute truth.
So, to prove Muhammad is the last prophet is very easy when you trust the WOrd of GOD.
peace
submitmj