1 John 5:13

That ye may know that ye have eternal life - I write to show your privileges - to lead you into this holy of holies - to show what believing on the Son of God is, by the glorious effects it produces: it is not a blind reliance for, but an actual enjoyment of, salvation; Christ living, working, and reigning in the heart.

And that ye may believe - That is, continue to believe: for Christ dwells in the heart only by Faith, and faith lives only by Love, and love continues only by Obedience; he who Believes loves, and he who Loves obeys. He who obeys loves; he who loves believes; he who believes has the witness in himself: he who has this witness has Christ in his heart, the hope of glory; and he who believes, loves, and obeys, has Christ in his heart, and is a man of prayer.