Finality of the Holy Prophet(sawa) in view of Shia scholars: –

All the Shia scholars believe Holy Prophet as the last messenger of Allah (swt). It is also clear that they believe in the immortality of Holy Quran and they also believe in the permanence of its teaching till the day of resurrection.

As for example Allama Tabarsi says in the interpretation of the verse 42 of Surah Fusselat
"Neither the books before the Quran invalidate it nor would there be any book after the Quran which would abrogate it. "

Tafseer e Majmaul Bayan Vol 9 pg 23.

Allama Tabatabai in his Tafseer e Mizan has said in interpretation of the verse "No Falsehood can approach it from the front or from behind it” (41:42) , It refers to the time when the Quran was revealed and also the time after it till the day of judgement.

Translation of Tafseer e Mizan Vol 17 Pg 604.

Another verse which talks about the immortality of the Holy Quran is the verse 19 of Surah Anam. Abu Futuh Razi, one of shia commentators in sixth century has said about the above verse which says "And the one to whom the Quran would reach"(6:19) , refers to the people of the ages of Holy Prophet and those who would follow him till the day of resurrection.

Tafseer e Rauzul Jinan Vol 7 pg 248.

Similarly other commentators like Mohammad Jawad Mugneeh has also said the same thing.

Finality of the Holy Prophet(sawa) in view of Sunni scholars: –

Anwarut Tanzeel wa Asrarut Taweel is one of the renowned and wellknown interpretation of the Holy Quran among Ahle Sunnah. The author of this Tafseer, Abdullah bin Umar Baizaawi , one of the scholars of the sixth century says regarding the verse , "And I warn you and those to whom this Quran reaches to"(6:19), it refers to the people of the ages of Holy Prophet and also who follow him till the day of resurrection. Another meaning is that I warn u all who r present here through this Quran and also those who would come after you till the day of judgement.
Anwarut Tanzeel wa Asrarut Taweel Vol 2 pg 157.

Jalal-al-Din Suyuti is one of the great and famous sunni scholars who has authored many books. Among his works is the famous Tafsir Al-Dur al-Manthur fi Tafsir al-Ma’athur. He has quoted traditions of Holy Prophet (sawa) as given below regarding the same verse,"And I warn you and those to whom this Quran reaches to"(6:19).

Holy Prophet (sawa) said: “Whoever the Quran reaches to, it is as if I have spoken to him”. After that Holy Prophet (sawa) recited this verse, "And I warn you and those to whom this Quran reaches to"(6:19) and then he said Oh People! Whoever receives a verse from quran, then the commands of Allah (swt) has reached to him whether he accept it or leaves it.

Tafsir Al-Dur al-Manthur fi Tafsir al-Ma’athur Vol 3 pg 8.

According to shia and sunni scholars, Since the commands of Allah(swt) is reaching to people till now through Holy Quran, no need arises for Allah(swt) to send a new prophet or a book!