The_Doc_Man
before the birth of Islam
Islam began at the time of Adam (peace be upon him) so I don't know what you are talking about.
285. The Messenger has believed in what was revealed to him from his Lord, and [so have] the believers. All of them have believed in Allaah and His angels and His books and His messengers, [saying], "We make no distinction between any of His messengers." And they say, "We hear and we obey. [We seek] Your forgiveness, our Lord, and to You is the [final] destination."
286. Allaah does not charge a soul except [with that within] its capacity. It will have [the consequence of] what [good] it has gained, and it will bear [the consequence of] what [evil] it has earned. "Our Lord, do not impose blame upon us if we have forgotten or erred. Our Lord, and lay not upon us a burden like that which You laid upon those before us. Our Lord, and burden us not with that which we have no ability to bear. And pardon us; and forgive us; and have mercy upon us. You are our protector, so give us victory over the disbelieving people."
Qur'an 2:285-6
But there is another factor here...
God sent SCRIPTURE to some Messengers.
Ibrahim (Abraham) - Souhouf (the Scrolls) in Hebrew
Musa (Moses) - Taurat (the Torah or the Law) & the Ten Commandments both in Hebrew
Dawud (David) - Zabur (the Psalms) in Hebrew
Isa (Jesus – son of Mary) - Injil, in Aramaic
Muhammad (the Seal of the Prophets) - Qur’an, in Arabic
Only the Qur'an and the 10 Commandments have survived in their original form. The 4 out of the original 79 gospels in the NT were written by man.
The Taurat has been corrupted over the ages and hence we do not have the original pristine original. Hence those, among the rabbis, who indeed changed the words of Allaah are major sinners.
Even the man made New Testamant has elements of truth in them where Jesus (peace be upon him) declares explicitly that there is only ONE God and has no partners.
1. Say : O ye that reject Faith!
2. I worship not that which ye worship,
3. Nor will ye worship that which I worship.
4. And I will not worship that which ye have been wont to worship,
5. Nor will ye worship that which I worship.
6. Unto you your religion, and unto me my religion.
Qur'an al Kafirun 109:1-6
Indeed, the religion in the sight of Allaah is Islam. And those who were given the Scripture did not differ except after knowledge had come to them - out of jealous animosity between themselves. And whoever disbelieves in the verses of Allaah, then indeed, Allaah is swift in [taking] account.
Qur'an 3:19
Muhammad (peace be upon him) could not read or write and he did not produce the Qur'an. All true Scripture comes from God via angel Gabriel and then to the Messengers and then written by the scribes, so him committing a sin in regards to scripture makes no sense.