1 John 2:3-5

New Revised Standard Version, Anglicised Catholic Edition

³ Now by this we may be sure that we know him, if we obey his commandments. ⁴ Whoever says, ‘I have come to know him’, but does not obey his commandments, is a liar, and in such a person the truth does not exist; ⁵ but whoever obeys his word, truly in this person the love of God has reached perfection. By this we may be sure that we are in him: