It can be hard to tell the difference between an immature Christian and an inauthentic one. According to the author of Hebrews, the main difference is growth. While it is possible for people with significant spiritual experiences to "fall away," those who receive the gift of salvation by grace through faith in Jesus cannot lose it. At the same time, God wants us to keep growing into this salvation—to build on foundational practices and graduate from milk to solid food, giving us practical wisdom for every situation in life.