What does the Bible say about falling away from faith?

In 1 Corinthians 10:12, Paul instructs believers, 'So if you think you are standing firm, be careful that you don't fall.' This indicates that spiritual complacency can lead to a fall from grace. While God's grace upholds true believers, those who think they stand may be deceived if their confidence is in mere religious experiences or group affiliation rather than genuine faith in Christ. The examples of the Israelites in the wilderness, most of whom did not enter the promised land due to unbelief, serve as a sobering reminder of the dangers of presuming one's standing based on outward appearances.