The true faith is vanquishing pride and submitting the self before God unconditionally. This submission is never complete unless intellect and passions attain total contentment and gratification in the ultimate reality of God. This is what heaven truly is.
In this sense, religious faith in its Islamic form maintains equilibrium between flux and stability, between change and changelessness. Positing an eternal entity does not commit it to being entirely metaphysical as it finds it easier to come to terms with the fluctuations of concrete existence.