Dear Shibboleth

The above statement contradicts with that fact that there're several versus and sayings of Prophet Muhammad ( PBUH ) that mentions the corruption of the scriptures of the jews and christians

Some versus that mentions this :

Speaking about jews:

[2:75] Do you then hope that they would believe in you, and a party from among them indeed used to hear the Word of Allah, then altered it after they had understood it, and they know (this).

[4:46] Some of those who are Jews change words from their context and say: "We hear and disobey; hear thou as one who heareth not" and "Listen to us!" distorting with their tongues and slandering religion. If they had said: "We hear and we obey: hear thou, and look at us" it had been better for them, and more upright. But Allah hath cursed them for their disbelief, so they believe not, save a few.

[5:13] But because of their breach of their covenant, We cursed them, and made their hearts grow hard; they change the words from their (right) places and forget a good part of the message that was sent them, nor wilt thou cease to find them- barring a few - ever bent on (new) deceits: but forgive them, and overlook (their misdeeds): for Allah loveth those who are kind.

[5:41] O Messenger! let not those grieve you who strive together in hastening to unbelief from among those who say with their mouths: We believe, and their hearts do not believe, and from among those who are Jews; they are listeners for the sake of a lie, listeners for another people who have not come to you; they alter the words from their places, saying: If you are given this, take it, and if you are not given this, be cautious; and as for him whose temptation Allah desires, you cannot control anything for him with Allah. Those are they for whom Allah does not desire that He should purify their hearts; they shall have disgrace in this world, and they shall have a grievous chastisement in the hereafter.

Regards

Mohammed’s family is not connected to any Ishmaelite tribe because Mohammed’s family didn’t leave Yemen until the 5th  century A.D., and that’s about  1,100 years  after the Ishmaelites disappeared.

The genealogy fabricated by Ibn-Ishak contradicts the sayings of Mohammed, who expressed his ignorance about his ancestors prior to his 17^th ancestor. Ibn Ishak was considered by the Muslim scholars of his time as being guilty of forgery and fabricating false genealogies.

Long before Ibn Ishak, Muslims who lived in Mohammed’s own time also fabricated genealogies in an attempt to connect Mohammed to the descendants of Ishmael. 

**Mohammed, himself, rejected all of these false genealogies, and he put limits regarding the genealogy of his ancestors. Regarding Mohammed’s own rejection of the false genealogies, Amru bin al-As wrote:

Mohammed genealogized himself regarding his ancestors until he reached al-Nather bin Kinaneh, then he said, “anyone who claimed otherwise or added further ancestors, has lied.”

By this, Mohammed confessed that neither he, nor anyone else, knew about his ancestors beyond al-Nather bin Kinaneh. Nather bin Kinaneh is the 17th ancestor in the genealogy which Mohammed recognized as true. Other narrations of the customs, or sayings, of Mohammed, called Hadiths, show Mohammed refused to be genealogized prior to Maad,  معدwho some suggested, was the 4th ancestor prior to al-Nather bin Kinaneh.

Many versions of Hadith of Mohammed coming from the followers of Mohammed all report that Mohammed opposed to be genelogized until Ishmael. All his closest contemporaries and followers considered the genealogies appearing at his time to be false. Among the people who reported Mohammed’s opposition to such genealogies were his wife, Aisheh, and his cousin, Ibn Abbas, one of the most important reporters of Mohammed’s Hadith.[iv]  Ibn Ishak went against what all these people had said by creating genealogies which connect the ancestors of Mohammed with Ishmael.