As we can see from numerous Quranic commentators, the “pure” heart isn’t referring to a believer who commits no sins or who is perfect. It is referring to a heart that is free of associating partners with God, that believes in Him without doubt and that believes in the Hereafter. In other words, if you’re a Muslim who worships Allah directly, have no doubt in His existence or that there is a Hereafter, then you already have one part of Qalbin Saleem: a sound, pure heart.