Allah Almighty says in the Holy Qur'aan:
"Those who will serve the Messenger, unlettered the Communicator of hidden news when they will find with them written in the Taurat and Injeel. He will bid them to do good and will forbid them from doing evil, and will make lawful for them clean things and will forbid for them unclean things, and will take off from them that burden and shackles which were upon them. Then those who believe in him and honour him and help him and follow that light which has been sent down with him, they are the persons who attained their objects."
[Surah 7: Ayat 157]
In the above mentioned verse Allah Subhanahu Wa Ta'ala says that those who wish for success in this world and in the next, should follow `the Rasool', `the Nabi' and `Ummi', three qualities or titles of the beloved Rasool Sallallahu Alaihi Wassallam which are also mentioned in the Taurat and Injeel (bible). The meaning of `Rasool' is `messenger' and `Nabi' is `one who gives information of the unseen'. The meanings of these two words are well known, however, the word `Ummi' requires some discussion. In an authentic book of Tafseer (interpretation of the verses of the Holy Qur'aan), `Tafseer Ruhul Ma'ani', it is stated that one reason for `Ummi' being a title of the Holy Prophet Sallallahu Alaihi Wassallam is because one of the names of Makkah is "Ummul Kurah". Because he was born and lived in Makkah for so many years and because of his connection with the city and he was given the title of "Ummi" just as someone from Madina would be known as Madani or someone from Iraq would be known as Iraqi. Another meaning given in the same book is `one who has never learnt to read or write' under the guidance of a teacher. It would be that his condition would be as if his mother had just given birth to him. Hazrat Muhammad Sallallahu Alaihi Wassallam was not taught by any human, angel or jinn, but by the Almighty, thus his knowledge is like an ocean and his teachings will always be pertinent, even till the Day of Judgement.
The knowledge of Hazrat Adam Alaihis Salaam was also very wide and for this reason the angels were ordered to bow before him.
As we are all aware, there are many languages in the world. Each one would have its own word to describe a particular thing. For example, in English we say water, in Arabic `maa', in Urdu `paani' and in Persian `aab'. In this manner the names of everything and the purpose of their creation were taught to Adam Alaihis Salaam. The great Ulama of Islam are of the opinion that the knowledge of the Holy Prophet Sallallahu Alaihi Wasallam is like an ocean and the knowledge of the other Prophets (On them be peace) is like a drop of that ocean. Thus the knowledge of Adam Alaihis Salaam is like that of a drop in comparison to that of the Holy Prophet Sallallahu Alaihi Wasallam
To say that an ordinary person is "Ummi" would signify a default in his personality. To understand this point consider this: Pride is considered to be a bad quality in character, but when we say that Almighty Allah has pride it is His praise, likewise the word "Ummi" when used for the Holy Prophet Sallallahu Alaihi Wassallam signifies his praise since without being educated by any worldly teacher he possesses knowledge about all creation.
In the words "Those who find written about him in the Tauraat and Injeel" indicates to us that the personality of Muhammad Sallallahu Alaihi Wassallam was discussed in the original, unchanged scriptures of the Jews and Christians.
Imaam Jalaludeen Suyuti Rahmatullahi Ta'ala Alaihi narrates that the grandson of Hazrat Abdullah Ibn Salaam Radiyallahu Anhuma (Hazrat Abdullah Ibn Salaam Radiyallahu Anhu was a very learned Jewish scholar of that time) says:
"I asked my grandfather about the Holy Prophet Sallallahu Alaihi Wassallam and he explained that when he became aware of the presence of Nabi Alaihis Salaam in Makkah he left his homeland to go there and when he met the Holy Prophet Sallallahu Alaihi Wassallam he was asked, `Are you Ibn Salaam? Are you the great scholar of the Jews?' He replied in the affirmative and the Holy Prophet Sallallahu Alaihi Wassallam asked him, taking the oath of Allah to answer the question truthfully, `Have you found my qualities described in the Book of Allah (Tauraat)?' Ibn Salaam replied, `I bear witness that you are the Messenger of Allah, and Allah will make you and your religion prevalent over the whole world. I have found your qualities in the Tauraat." The following verse was then read, `Oh giver of the unseen news, undoubtedly we have sent you as a witness, and a giver of glad-tidings, and a warner. You are my servant and Messenger, I have named you Mutawakil (one who has complete trust in Allah)....." [Al-Khasaaisul Kubra, Vol 1]
Imaam Jalaludeen Suyuti Rahmatullahi Ta'ala Alaihi narrates that the uncle of our beloved Nabi Sallallahu Alaihi Wassallam, Hazrat Abbas Radiyallahu Anhu once enquired from Kaabul Akhbaar a great Jewish scholar of his time why he accepted Islam during the time of Hazrat Umar Radiyallahu Anhu instead of in the time of Muhammad Sallallahu Alaihi Wassallam or the time of Hazrat Abu Bakr Siddique Radiyallahu Anhu. He replied, "My father wrote something for me from the Tauraat, he closed it and thereafter he gave it to me, and said, `Act upon this and follow it.' My father made me promise to do as he said and not to open it until a difficult time comes. Time passed and Islam spread far and wide, and I found nothing but good in the religion and at that point I opened the letter and therein I found a description of the Holy Prophet Alaihis Salaam and his Ummah. Therefore I have come now and accepted Islam." Another Sahabi asked Ka'abul Akhbaar, "Have you found anything about our beloved Rasool (Sallallahu Alaihi Wassallam) in the Tauraat?" He said, "I have found written, `Muhammad is the Messenger of Allah, his birth will be in Makkah and thereafter he will travel to Madina."
In a Hadith narrated by Hazrat Abu Hurairah Radiyallahu Anhu, our Holy Prophet Sallallahu Alaihi Wassallam said,
"When Allah revealed the Tauraat to Moosa (Alaihis Salaam) and when he received the verses regarding this Ummah he prayed, `Oh Allah, I have found in the Tauraat that there will be an Ummah that will come last but yet their positon will be the best and intercession regarding them will be accepted, Oh Allah make them my Ummah.' Allah replied, `This is the Ummah of Muhammmad (Sallallahu Alaihi Wassallam).' Thereafter Moosa (Alaihis Salaam) said, `Their holy scripture will be stored in their hearts and they will recite it from there, Oh Allah make them my Ummah.' Allah replied that, `This is the Ummah of Muhammad (Sallallahu Alaihi Wassallam).'Then Moosa (Alaihis Salaam) asked, `That Ummah that has knowledge of the past as well as future, Oh Allah, make them my Ummah.' Again Allah replied,`That is the Ummah of Muhammad (Sallallahu Alaihi Wasallam)."
From this, it is clear that the previous Ummahs were informed about the coming of our Beloved Rasool Sallallahu Alaihi Wasallam. How fortunate are we not that the status of this Ummah has also been described in the previous scriptures by virtue of being the followers of the Beloved of Allah, Sayyidina wa Mawlana Muhammad Sallallahu Alaihi Wassallam.


http://www.islamicmiracles.net/taurat_last_prophet_p1.htm