Muhammad the Messenger of Islam

 Muhammad S. was a progeny of Abrahim and Abrahim as. was a MUSLIM

3:65 Ye People of the Book! Why dispute ye about Abraham, when the Law and the Gospel Were not revealed Till after him? Have ye no understanding? 3:66 Ah! Ye are those who fell to disputing (Even) in matters of which ye had some knowledge! but why dispute ye in matters of which ye have no knowledge? It is God Who knows, and ye who know not! 3:67 Abraham was not a Jew nor yet a Christian; but he was true in Faith, and bowed his will to God's (Which is Islam), and he joined not gods with God. 3:68 Without doubt, among men, the nearest of kin to Abraham, are those who follow him, as are also this Apostle and those who believe: And God is the Protector of those who have faith.

(this Apostle=Muhammad (pbuh)

Muhammad (s)  was Messenger:

7:157[Those who follow the messenger, the Prophet who can neither read nor write, whom they will find described in the Torah and the Gospel (which are) with them. He will enjoin on them that which is right and forbid them that which is wrong. He will make lawful for them all good things and prohibit for them only the foul; and he will relieve them of their burden and the fetters that they used to wear. Then those who believe in him, and honour him, and help him, and follow the light which is sent down with him: they are the successful.

[7:158] Say (O Muhammad): O mankind! Lo! I am the messenger of Allah to you all - (the messenger of) Him unto Whom belongeth the Sovereignty of the heavens and the earth. There is no God save Him. He quickeneth and He giveth death. So believe in Allah and His messenger, the Prophet who can neither read nor write, who believeth in Allah and in His Words, and follow him that haply ye may be led aright.

35:25 And if they call you a liar, so did those before them indeed call (their apostles) liars; their apostles had come to them with clear arguments, and with scriptures, and with the illuminating book.

Muhammad S. was mentioned in old Scriptures:

7:157     "Those who follow the apostle, the unlettered Prophet, whom they find mentioned in their own (scriptures),- in the law and the Gospel;- for he commands them what is just and forbids them what is evil; he allows them as lawful what is good (and pure) and prohibits them from what is bad (and impure); He releases them from their heavy burdens and from the yokes that are upon them. So it is those who believe in him, honour him, help him, and follow the light which is sent down with him,- it is they who will prosper."

7:158     Say: "O men! I am sent unto you all, as the Apostle of God, to Whom belongeth the dominion of the heavens and the earth: there is no god but He: it is He That giveth both life and death. So believe in God and His Apostle, the Unlettered Prophet, who believeth in God and His words: follow him that (so) ye may be guided."

Islam is not Muhammadism: (Muslims do not worship Muhammad S.)

10:104 Say (O Muhammad): O mankind! If ye are in doubt of my religion, then (know that) I worship not those whom ye worship instead of Allah, but I worship Allah Who causeth you to die, and I have been commanded to be of the believers.

10:105 And, (O Muhammad) set thy purpose resolutely for religion, as a man by nature upright, and be not of those who ascribe partners (to Allah).

10:106 And cry not, beside Allah, unto that which cannot profit thee nor hurt thee, for if thou didst so then wert thou of the wrong-doers.

10:107 If Allah afflicteth thee with some hurt, there is none who can remove it save Him; and if He desireth good for thee, there is none who can repel His bounty. He striketh with it whom He will of his bondmen. He is the Forgiving, the Merciful.

10:108 Say: O mankind! Now hath the Truth from your Lord come unto you. So whosoever is guided, is guided only for (the good of) his soul, and whosoever erreth erreth only against it. And I am not a warder over you.

10:109 And (O Muhammad) follow that which is inspired in thee, and forbear until Allah give judgment. And He is the Best of Judges .