This claim assumes that the faith of the ancient Israelites was Islam; but as explained in the last section, the religion of the ancient Israelites can be described in such a way only according to the literal meaning of the word islam – surrender or submission. It is a stretch, however, to claim that the religious practices of ancient Israel were entirely the same as the modern religion of Islam, the details of which are largely based on the practices of Muhammad. Such a claim is unsubstantiable.
It is true that Muslims generally emphasize a few of the more noticable practices of ancient Israel that are not as emphasized among most Jews in the present era, such as prostration and modesty, but this is not proof that the modern religion of Islam is identical to the religious observance of the ancient Israelite prophets.
There are numerous laws contained in the Torah and known to have been kept by the ancient Israelites that are not mentioned in the Qur’an and not practiced by Muslims.
There are also ancient practices of the historical faith of Israel that the Qur’an testifies to and yet the Islam of today does not observe, ie: the Sabbath, forbidden fats, and certain relationship restrictions during a woman’s monthly cycle. Despite the decline of prostration in prayer and modesty among most Jews, something largely attributable to the influence of European culture which we now see happening among Muslims in the realm of modesty, Jews still maintain many religious observances that were kept by the ancient Israelite prophets that the average Muslim is entirely unaware of.
Despite the decline of prostration as a regular part of daily Jewish prayer, the Jewish parallel to Shari’a law known as halakha, still maintains that Jews are to prostrate as a part of regular prayer and that Jews are to dress modestly.
Though the level of religious observance among Jews may have changed, the Torah’s instruction is just as it was thousands of years ago. Consequently, it is not accurate to equate the ignorance of Jews as to the teachings of the faith they claim to follow with corruption of that same faith, any more than we should equate ignorance of Islamic teaching among Muslims, something many Muslims will admit to, with the corruption of Islam as taught by Muhammad. In fact, Sunni Muslims consider Shia Islam corrupt, and Shias consider Sunni Islam corrupt; both consider the other even smaller sects of Islam corruptions of Islam. Consequently, any honest Muslim must admit that Islam is certainly corrupted to some extent – but the corruption of a religion’s teachings does not necessarily mean that the religion’s scripture is itself corrupt or unreliable.