1 John 2:2-6

And He [that same Jesus] is the propitiation for our sins [the atoning sacrifice that holds back the wrath of God that would otherwise be directed at us because of our sinful nature—our worldliness, our lifestyle]; and not for ours alone, but also for [the sins of all believers throughout] the whole world. And this is how we know [daily, by experience] that we have come to know Him [to understand Him and be more deeply acquainted with Him]: if we habitually keep [focused on His precepts and obey] His commandments (teachings). Whoever says, “I have come to know Him,” but does not habitually keep [focused on His precepts and obey] His commandments (teachings), is a liar, and the truth [of the divine word] is not in him. But whoever habitually keeps His word and obeys His precepts [and treasures His message in its entirety], in him the love of God has truly been perfected [it is completed and has reached maturity]. By this we know [for certain] that we are in Him: whoever says he lives in Christ [that is, whoever says he has accepted Him as God and Savior] ought [as a moral obligation] to walk and conduct himself just as He walked and conducted Himself.