One of the main signs that it's a cult, rather than the Truth, the Way and the Light, is the corruption and adulteration of Scripture. However, the other clear sign is who they believe Jesus to be.
Following is a list that shows some of the strong differences between Jesus and Mohammed. The Muslims revere Mohammed as the greatest of prophets, yet Jesus clearly demonstrated greater authority, teaching, and miracles than Mohammed ever did. Why would anyone want to follow Mohammed over Jesus when Jesus claimed to be divine, performed many miracles, said that He alone was the truth, raised people from the dead, and rose from the dead Himself, and Mohammed did none of these things. However, Mohammed did have people killed, spread his religion through war, married a very young girl and had relations with her when she was nine years of age, and taught hatred of Jews and Christians.
1) Jesus ascended bodily into heaven. Mohammed did not.
2) Jesus is called the "Word of God". Mohammed is not.
3) Jesus spoke at His birth (Sura 19:29,30)
4) Jesus had supernatural knowledge (Sura 1:49)
5) Jesus was endowed with the Holy Spirit (Sura 4:171)
6) Jesus was called "Spirit in Him" (Sura 4:171)
I don’t Islam, but I’ve read 94:10 and it affirms the Bible as a book of God.
The Bible affirms the Christ and the Trinity.
Either Muhammad has affirmed the Bible to be true, therefore the Christ and the Trinity to be true, or he is a liar. Him being a liar does not take away from the Bible’s claims one bit.
Muslims hate that argument because they can’t answer it.
Any efforts to undermine Islam is worth it.
I’ve recently found videos from David Wood and they are fantastic.
Start here;
https://www.youtube.com/user/Acts17Apologetics/videos?view=0&shelf_id=1&sort=dd
Some of my favorites include;
The Truth about the Hajj
https://www.youtube.com/watch?v=Rxj41M-xwa0
The Sheepgate Conspiracy: How Muhammad’s Wives Changed the Quran (David Wood)
https://www.youtube.com/watch?v=0taTSaUO2hM
Muhammad: The White Prophet with Black Slaves
https://www.youtube.com/watch?v=tZxH4QYLRQY
I would also recommend;
Apostate Prophet
https://www.youtube.com/channel/UCzREuchzOqiawpEpvEM0Tyg
It’s my understanding that in Islam, Jesus is revered (in theory) as one in a long line of prophets paving the way to Mohamed, and that Christians are considered (again, in theory) as “people of the Book” worthy of respect. Of course, in practice there is usually little respect for either Christianity or Christians in Islam. Those Muslims who actually do so are usually branded as heretics and traitors by their fellows.