The Number of Messengers and Prophets

Question:

What is the number of the Prophets and Messengers? And if we do not believe in some of them because we do not know them, does this constitute disbelief on our part? How many Books did Allah reveal?

Answer:

It has been mentioned in a number of Prophetic traditions that the number of Prophets is 124,000, among whom were 313 Messengers. It is also reported that there were 8,000 Prophets. Such traditions are mentioned in the book of Ibn Kathir, Tafsir Al-Qur'an Al-Athim, at the end of Surah An-Nisa', where Allah says:
...and Messengers we did not mention to you. The traditions under this subject, although they are numerous, are not all authentic. It is better in this case not to speculate their number.

It is the duty of the Muslims to believe in those whom Allah and His Messenger mentioned by name in particular, and to believe in all of the rest of them in general. Allah has condemned Jews for making distinction between some Prophets and others. He describes them saying:

And they say, "We believe in some and disbelieve in others."

We believe in every Prophet and every Messenger Allah sent in a certain period of time; but we also believe that his laws were applicable for his own people and time.

As for the number of the revealed Books, it is mentioned in a long Hadith which is reported by Abu Tharr who said that there were 104 Books. Ibn Kathir quoted it in his commentary on the above mentioned Verse. Only Allah knows how authentic are such traditions. Allah mentions by name the Tawrah, the Injil, Az-Zabur, the Suhuf of Ibrahim and Musa. Therefore we believe in them and believe there are many Books of Allah which we do not know, but it is sufficient for us to believe in them in general.

Source:
Fatawa Islamiyah, Vol. 1 Pages 68-69-70