Many people down the ages have led religious lives that couldn’t necessarily be called spiritual, though they may have mistaken one for the other. When spirituality becomes hypocrisy, God springs a surprise that separates the true from the false: “My Lord says, ‘Because these people approach me with the mouth and pay me homage with their lips, while their heart remains far from me—their piety toward me consisting of commandments of men learned by rote—therefore it is that I shall again astound these people with wonder upon wonder, rendering void the knowledge of their sages and the intelligence of their wise men insignificant.’” (Isaiah 29:13–14).
When the materialistic lifestyle of God’s people turns their religion into a superficial version of what it once was, they may not even be aware of it: “O you deaf, listen; O you blind, look and see! Who is blind but my own servant, or so deaf as the messenger I have sent? Who is blind like those I have commissioned, as uncomprehending as the servant of Jehovah—seeing much but not giving heed, with open ears hearing nothing?” (Isaiah 42:18–20). God’s response is to restore his truth to them—in part through the Book of Isaiah: “In that day shall the deaf hear the words of the book and the eyes of the blind see out of gross darkness” (Isaiah 29:18; 30:8–9).