Jesus went down to the eight disciples who were awaiting him below. And the four narrated to the eight all that they had seen: and so there departed that day from their heart all doubt of Jesus, save [from] Judas Iscariot, who believed naught. Jesus seated himself at the foot of the mountain, and they ate of the wild fruits, because they had not bread.
            Then said Andrew: 'Thou hast told us many things of the Messiah, therefore of thy kindness tell us clearly all.' And in like manner the other disciples besought him.
            Accordingly Jesus said: 'Everyone that worketh worketh for an end in which he findeth satisfaction. Wherefore I say unto you that God, verily because he is perfect, hath not need of satisfaction, seeing that he hath satisfaction himself. And so, willing to work, he created before all things the soul of his messenger, for whom he determined to create the whole, in order that the creatures should find joy and blessedness in God, whence his messenger should take delight in all his creatures, which he hath appointed to be his slaves. And wherefore is this, so save because thus he hath willed?
             'Verily I say unto you, that every prophet when he is come hath borne to one nation only the mark of the mercy of God. And so their words were not extended save to that people to which they were sent. But the messenger of God, when he shall come, God shall give to him as it were the seal of his hand, insomuch that he shall carry salvation and mercy to all the nations of the world that shall receive his doctrine. He shall come with power upon the ungodly, and shall destroy idolatry, insomuch that he shall make Satan confounded; for so promised God to Abraham, saying: "Behold, in thy seed I will bless all the tribes of the earth; and as thou hast broken in pieces the idols, O Abraham, even so shall thy seed do."'
            James answered: 'O master, tell us in whom this promise as made; for the Jews say "in Isaac," and the Ishmaelites say 'in Ishmael." '
            Jesus answered: 'David, whose son was he, and of what lineage?'
           James answered: 'Of Isaac; for Isaac was father of Jacob, and Jacob was father of Judah, of whose lineage is David.'
           Then said Jesus: 'And the messenger of God when he shall come, of what lineage will he be?'
           The disciples answered: 'Of David.'
           Whereupon Jesus said: 'Ye deceive yourselves; for David in spirit calleth him lord, saying thus: "God said to my lord, sit thou on my right hand until I make thine enemies thy footstool. God shall send forth thy rod which shall have lordship in the midst of thine enemies." If the messenger of God whom ye call Messiah were son of David, how should David call him lord? Believe me, for verily I say to you, that the promise was made in Ishmael, not in Isaac.'

An Islamic Perspective and Commentary
Ishaq Zahid

Prophet Muhammad (peace be on him) is a direct descendant of Ishmael. His geneology chart may be found at  The Holy Quran asserts that the message of Muhammad is not limited to arabs, but is universal.

038.087 "This is no less than a Message to (all) the Worlds.
021.106 Verily in this (Qur'an) is a Message for people who would (truly) worship God.
021.107 We sent thee not, but as a Mercy for all creatures.

025.001 Blessed is He who sent down the criterion to His servant, that it may be an admonition to all creatures;-
025.002 He to whom belongs the dominion of the heavens and the earth: no son has He begotten, nor has He a partner in His dominion: it is He who created all things, and ordered them in due proportions.
025.003 Yet have they taken, besides him, gods that can create nothing but are themselves created; that have no control of hurt or good to themselves; nor can they control death nor life nor resurrection.
025.004 But the misbelievers say: "Naught is this but a lie which he has forged, and others have helped him at it." In truth it is they who have put forward an iniquity and a falsehood.
025.005 And they say: "Tales of the ancients, which he has caused to be written: and they are dictated before him morning and evening."
025.006 Say: "The (Qur'an) was sent down by Him who knows the mystery (that is) in the heavens and the earth: verily He is Oft-Forgiving, Most Merciful."

Prophet Muhammad is the last messenger sent by God for the guidance of mankind till the Day of Judgement. The revelations sent to him can be found in the Quran in the original form without a slight alteration.