The theist, who believes in God, whenever he is distressed, whenever he is facing some problem, he turns towards God: "God save us." That is nice, very nice. They are called pious. When there are problems, when they look towards God, such person is called pious. It is described in Bhagavad-gītā, catur-vidhā bhajante māṁ sukṛtinaḥ arjuna. Sukṛtina means pious. Su means good, and kṛtina means activities. And similarly, the opposite number, that is called duṣkṛtina. Du means... Duṣ means bad, and kṛtina means activities.
So there are two classes of men. One class of men who are pious... Pious means those who are regularly following the religious principles. It does not matter what religion you follow. If you follow the religious principles in whichever religion you accept, then you are pious. If you do not follow the religious principles, then you are impious, duṣkṛtina.