A religion of notions is but a shadow; true godliness is engraved upon the heart by the Spirit. This highlights the crucial difference between intellectual assent to Christianity and true, Spirit-wrought godliness. A "religion of notions" refers to a faith that exists merely in the mind—one that acknowledges doctrine but lacks spiritual transformation. Such a faith is external, superficial, and powerless to save. It is compared to a "shadow" because, like a shadow, it has the form of religion but lacks its substance (2 Timothy 3:5). Scripture warns against this kind of empty profession, as seen in James 2:19, where even the demons believe in God but remain unredeemed. Similarly, Jesus rebukes the Pharisees in Matthew 15:8, saying, “This people honors me with their lips, but their heart is far from me.” Intellectual knowledge alone does not produce genuine holiness; it is merely an appearance of faith without its life-giving power.

In contrast, true godliness is not just known but engraved upon the heart by the Holy Spirit. This imagery recalls Jeremiah 31:33, where God promises, “I will put my law within them, and I will write it on their hearts.” True Christianity is a work of divine grace, transforming the believer’s affections, will, and desires. The Holy Spirit not only enlightens the mind but renews the heart, making a person love and obey God from the inside out (Ezekiel 36:26-27). Paul echoes this in 2 Corinthians 3:3, stating that believers are “a letter from Christ... written not with ink but with the Spirit of the living God, not on tablets of stone but on tablets of human hearts.” In sum, true godliness is not about knowing about Christ but being made new in Christ—a transformation that only the Spirit can accomplish.