In the Quran. The actual unaltered message of Jesus(pbuh) doesn't exist anymore. Well maybe in the books that are hidden away in the Vatican, who knows.

The 2 major surfing Christian thoughts were Jewish Christians and Pauline Christians. The Romans burdened almost all of the books that weren't made part of the state religion and any non Pauline Christians were then persecuted and they had to flee to Persia and other non roman lands.

We have in our historical documents that roman Hiracleus confirmed that Prophet Muhammad(pbuh) has been prophesized in Christian tradition. But those Prophecies he was referring to are not found in the Bible so he as a Christian theologian and king had access to Christian religious books outside what the compiled bible has. Ethiopian Christian follow a different bible where some books are missing others are added. We have some of the truth still preserved in the compiled bible but by no means is it all the truth. We know much clear trinity is missing in the bible which is why some people in history tried to change the compiled bible and added some and changed some verses in order to make trinity seem like a solid concept in the bible. These were then redacted in the NIV. God is the creator he doesn't father children, nor does he allow worship of any except him alone with out any other persons that can be consider share Godhood with in his being.

It's an accepted fact that bible compilation had a process where books that didn't fall under the Pauline Christian doctorine were left out.

Muslims have an elderly companion Salman Al-Farsi. He was born a Zoroastrian converted to Christianity and by the dying monk of his monestary he was sent to look for the Prophet whose time is near arrival. He was given sign about the Prophet To come, but these signs are non existent in the bible. Salman Al-Farsi made it to Arabia after having been captured as a slave, where he confirmed Prophet Muhammad(pbuh) fulfilled those signs and then Salma(ra) became a muslim.