For purposes of this discussion, Muslims and Christians agree that very little changes. In fact, we might agree that God is the only being not subject to change. But this refers to his character and attributes, not to our understanding of God. More on this later. Similarity is not sameness.
Similarity is a flexible, fluctuating, pliable concept.
Sameness is firm, unbreakable, absolute. Two things, persons or ideas may share any number of similarities. That they are partners in similarity, by definition, makes them not the same. Sameness and similarity are mutually exclusive concepts. The Ford and the Fiat are similar.