When Prophet Muhammad (PBUH&HP) was writing letters to the Heads of neighboring states, he referred to Jesus Christ (PBUH) as the messenger of Allah and then invited them to Islam. In his letter to Nagaci, the king of Ethiopia, he wrote: 

“… He, the King, the Holy peace insured dominant, and I bear witness that Jesus son of Mary, the Spirit of Allah and his speech was delivered to the Virgin Mary the good bunker. Allah created Jesus from his soul, just as he created Adam with his hand, and I invite you and your soldiers to Allah Almighty, has reached and advised receive my advice, and peace be upon those who follow guidance”.

Insisting on the fact that he knew Jesus (PBUH) and that he was the son of Mary, he wanted them to know that Islam is no different from true Christianity. The Quran, on the other hand, insists on this and reveals the fact that his name was stated before in the holy books:

 "Those who follow the Messenger, the unlettered prophet, whom they find written in what they have of the Torah and the Gospel, who enjoins upon them what is right and forbids them what is wrong and makes lawful for them the good things and prohibits for them the evil and relieves them of their burden and the shackles which were upon them. So they who have believed in him, honored him, supported him and followed the light which was sent down with him - it is those who will be the successful." (7:157)

But is that true? 

Here we are going to discuss some of those verses and words.

 1. Prophet Muhammad (PBUH&HP) in Deuteronomy 

“I will raise up a prophet from among their countrymen like you, and I will put My words in his mouth, and he shall speak to them all that I command him. It shall come about that whoever will not listen to My words which he shall speak in My name, I Myself will require it of him. But the prophet who speaks a word presumptuously in My name which I have not commanded him to speak, or which he speaks in the name of other gods, that prophet shall die.”(18:18)

Al-Samawal Al-Maghribi was a Jewish mathematician who converted to Islam and had interpretations of the verses of the Old and New Testament. He interprets this verse as referring to Prophet Muhammad (PBUH&HP). The description given in this verse about the future prophet is referring to Prophet Muhammad (PBUH&HP) since it’s similar to the description given before about the children of Esau (Jesus). There is another verse that is referring to Prophet Muhammad (PBUH&HP) in his point of view: 

"The Lord came from Sinai, and dawned on them from Seir; He shone forth from Mount Paran, And He came from the midst of ten thousand holy ones; At His right hand there was flashing lightning for them.” (33:2)

Al-Maghribi states that in this verse, Mount Sinai refers to Moses, Mount Seir refers to Jesus, and Mount Paren refers to Prophet Muhammad (PBUH&HP). [1] 

2. Prophet Muhammad (PBUH&HP) in Isaiah

This chapter is shared between the Hebrew Bible and the Old Testament of the Christian Bible. In verses 1 to 4 of this chapter, we read: 

“Behold, My Servant, whom I uphold; My chosen one in whom My soul delights. I have put My Spirit upon Him; He will bring forth justice to the nations. "He will not cry out or raise His voice, Nor make His voice heard in the street. "A bruised reed He will not break and a dimly burning wick He will not extinguish; He will faithfully bring forth justice. "He will not be disheartened or crushed Until He has established justice in the earth; And the coastlands will wait expectantly for His law.” (42:1-5)

According to the verses above, a prophet was coming from the children of Qedar, the second son of Ishmael [2], and also the nomadic Arab tribe, which was known as the most significant organized Arab tribe [3]. He is also sent to the same tribe to guide them on the right path. The other point about the prophethood of Muhammad (PBUH&HP) mentioned in this verse is that his religion was universal, willing to stand against gods and goddesses. Everyone waited for his coming, and different tribes would follow him. 

3. Prophet Muhammad (PBUH&HP) in John 

“I will ask the Father, and He will give you another Helper, that He may be with you forever; that is the Spirit of truth, whom the world cannot receive, because it does not see Him or know Him, but you know Him because He abides with you and will be in you. “ (14:16-17)

Muslims’ interpretation of this verse states that the two words meaning comforter and famous, were used interchangeably and Jesus in prophesying the coming of Prophet Muhammad (PBUH&HP). [4] They also relate these verses to a verse of the Quran about Jesus Christ, telling his people about the coming of the next prophet:  

“And [mention] when Jesus, the son of Mary, said, "O children of Israel, indeed I am the messenger of Allah to you confirming what came before me of the Torah and bringing good tidings of a messenger to come after me, whose name is Ahmad." But when he came to them with clear evidence, they said, "This is obvious magic.” (61:6)

According to this verse, the name Ahmad is given for Prophet Muhammad (PBUH&HP), and it means the praised one. According to the translations of the holy bible, the word periklutos means the celebrated or praised one means Ahmad. The word is repeated in John 14, John 15 and 16.

According to the verses above, the coming of Muhammad (PBUH&HP) was prophesied by the former prophets. And many Jews and Christians were aware of the coming of a new prophet. However, many of them rejected his invitation. Why? 
You will find out in the next article. 

References

1. al-Maghribi, Al-Samawal; Confutation of the Jews (in Arabic). Syria: Dar Al Qalam, 1989, 75-77
2.  Besharat Ahdein
3.  Stearns and Langer, 2001, p. 41.
4.  Zepp, Ira G. A Muslim Primer: Beginner's Guide to Islam. Vol. 1. University of Arkansas Press, 2000, 50-51
    

Every age has its defining genius, every culture its own Aristotle, Leonardo or Goethe. For classical Islam, one of those figures is unquestionably Ibn Sina or Avicenna (his Latinized name). A marvelous man by whose eighteenth birthday his fame as a physician was so great that he was summoned to treat the dying Samanid king of Bukhara (976-97 A.C) when all the talented court physicians had given up hope of his recovery. To the great astonishment of all, he was given the privilege of using the court's remarkable library which was the highest award for his future successes.

It is hard to describe Avicenna in any word but superlative. He wrote almost 450 treatises on a wide range of subjects, of which around 240 have survived. His intellectual achievements encompassed not only medicine, but philosophy, law, science, music, poetry, mathematics, and statecraft. Even his life was the stuff of legends.

The only source of information for the first part of Avicenna's life is his autobiography, as written down by his student Juzjani. Now let's have a glimpse at his life in his own words:

“My father Abdullah was from Bukhara. Bukhara at that time was one of the greatest cities in Persia. He was appointed as a Samanid governor married to my mother Setareh, and I was born there in 980 A.D. They called me Hussain, some years later my father was posted to Bukhara, where I received my early education in literature and Quran. From the very beginning I made such remarkable progress in my education that at the age of 10, I had completely memorized the Quran. Abu Abdullah al Natili, a leading philosopher of his time, visited Bukhara and stayed at our home. I learned logic, geometry, and astronomy from him. I soon surpassed my teacher and studied medicine, physics, and metaphysics by myself and mastered all these subjects before I was 17 years old. Then, I started writing at the age of 21”.

Ibn Sina's chief work is the monumental "Al-Qanun," which is over one million words in length, in medicine. The instructions of this book were Europe's pharmacopeia for five centuries after his death.  Al-Qanun discusses the whole field of medicine in an attempt to codify all the existing medical knowledge.

Another important work, a commentary on the work of Aristotle, was designed to set out the philosophies of ancient Greeks. Al Kitab ash-Shifa (the book of healing) is the most extended treatise on philosophy ever written by a single man.

In the end, the repeated travels and exacting political and intellectual preoccupations of Ibn Sina deteriorated his health. He was suffering from colic, and he made some extraordinary efforts towards his treatment.

He became bedridden in Hamadan (Iran), and died at the age of 57 in 1037 A.D., being the victim of a disease in which he was a specialist. His grave in Hamadan is yearly visited by a large number of admirers.

As one of the historians said, Avicenna is like a meteor, which flashed across the sky, illuminating the whole world with his brilliance, and in whose afterglow we still perceive the world around us.

References:

1.  Avicenna