If the first inward thought is not warded off, it will generate a desire, then the desire will generate a wish, and the wish will generate an intention, and the intention will generate the action, and the action will result in ruin and divine wrath. So evil must be cut off at its root, which is when it is simply a thought that crosses the mind, from which all the other things follow on.
Al-GhazaliMen have such a good opinion of themselves, of their mental superiority and intellectual depth; they believe themselves so skilled in discerning the true from the false, the path of safety from those of error, that they should be forbidden as much as possible the perusal of philosophic writings.
Al-Ghazali