remains in Him: The Greek word menō means “to remain” or “to stay.” It describes “abiding” or “remaining” in Christ (John 15:1–8) instead of departing into false teaching. When we live in ongoing and dependent fellowship with Christ, and when we remain faithful to the apostles’ teaching, we will not continue in sin.
continues to sin: This verb describes sin as an ongoing or repeated action. John was not saying that a single act of sin means a person does not know God. Instead, if a person continues to sin without turning away from that sin, that pattern shows a lack of relationship with God.