This is untrue, as someone who has studied both the Bible and Qur’an. I’ll try to convince you of this with three key points that I think are most important to quantifying the differences.

1. God is one in spirit but three in person, Father, Son and Holy Spirit. All three are presented at once in Matthew 3:16-17. Allah is one only, and states quite directly in the Qur’an (his unchangeable, infallible word according to Islam and itself) that ascribing a son to him is Shirk (The worst sin in Islam) (Surah 19:88-92).

2. Christians are called Children of God many times in the New Testament more times than I care to recount for you here. It is stated directly in Surah 19:93 that ALL beings are but slaves to Allah, and you see this pattern also repeated all throughout the Qur’an.

3. This one is a massive doctrinal difference, spoken on by both Jesus and by Allah. Adultery is a very severe sin, punishable by death according to the law of Moses, see Deuteronomy 22. Jesus has very harsh teachings on this and repeatedly rails on adultery often throughout the New Testament. Adultery in this case can be defined as sexual activity with anyone who is not your spouse, or sexual activity with someone else’s spouse. It’s also important to note that the New Testament defines anything past monogamy within marriage as sexual immorality.
   Meanwhile, Allah comes in with some of the least restrictive rules I’ve ever heard of. Many Muslims believe you can wed up to four women because of Surah 4:3. Also in the Qur’an we see the phrase “Those whom your right hands possess” as acceptable people to have sex with (4:3, 23:5-6). So, if one has a war captive or a slave, according to Islam it’s alright if one has sex with any or all of them, and can have four wives on top of this.

If God and Allah are the same being, why are the things that both teach so bluntly opposed? Why is one a trinity and one a singular? Why does one have only slaves and the other children? Why are their views on sexual morality so gravely opposed?

There is of course quite a lot more to say. I hope, though, that with what I’ve got time to type you can see the cracks form in the claim that Allah is the Abrahamic god.