#1 the Abrahamic god and its books at the time of the Koran, were in your geographic location. This is a stone cold fact. Its common knowledge.
So we have a people who possessed the bible already in their hands, who produced another version, the same way EVERY new religion starts by plagiarizing previous religions.
Or
#2 a god did it.
And god does not even scientifically exist, and we can see how the Abrahamic god was produced and created by combining two Canaanite deities after Israelites had existed for over 600 years. And at that time 622 BC, monotheism was still not that popular in Israelite cultures as the bible is full of scripture that describes the fight against polytheism.
History of ancient Israel and Judah - Wikipedia, the free encyclopedia
Israelite monotheism evolved gradually out of pre-existing beliefs and practices of the ancient world.[76] The religion of the Israelites of Iron Age I, like the Canaanite faith from which it evolved[77] and other ancient Near Eastern religions, was based on a cult of ancestors and worship of family gods (the "gods of the fathers").[78] Its major deities were not numerous El, Asherah, and Yahweh, with Baal as a fourth god, and perhaps Shamash (the sun) in the early period.[79] By the time of the early Hebrew kings, El and Yahweh had become fused and Asherah did not continue as a separate state cult,[79] although she continued to be popular at a community level until Persian times.[80] Yahweh, later the national god of both Israel and Judah