https://www.mljtrust.org/sermons-online/ephesians-5-7-8/children-of-light/

What does it mean to walk as children of the light and what are the implications for the Christian life? What is sanctification and what is the Christian’s role in it? In this sermon on Ephesians 5:6–7 titled “Children of Light,” Dr. Martyn Lloyd-Jones tackles these questions. Sanctification in the New Testament, as seen in these verses, follows this principle: it is not something received or taken but rather results from a correct understanding of the truth that leads to application. In this passage, Paul says that believers have become children of the light, and that this understanding should cause them to walk as such— a perfect case of sanctification resulting from a correct understanding of God’s word. It is active, not passive. The difference between a Christian and a nonbeliever, Dr. Lloyd-Jones says, is the difference between being in the light and being in darkness. Several other passages in Scripture use this same analogy. The change that takes place when one follows Christ is massive— from darkness to light, from death to life. It is not a mere topical change, but is rather a radical change from the inside out.