That's right! The "Holy" book of "Allah", who is all-knowing (Sura 49:13), doesn't understand what the Bible teaches!

Sura 5:37 - "They have certainly disbelieved who say, "Allah (AKA, God) is the third of three." And there is no god except one God. And if they do not desist from what they are saying, there will surely afflict the disbelievers among them a painful punishment."

This is clearly talking about the trinity (The third of thee), but Muhammad did not understand the trinity.

God is one God just like this verse says, but he is ons God who is "manifest" in 3 forms. It's similar to how our mind, body, and soul are 3 distinct features of us, but they made up the whole body (And you cannot be the whole you if you are missing one of them)