3By this we know that we have come to know Him, if we keep His commandments.4The one who says, "I have come to know Him," and does not keep His commandments, is a liar, and the truth is not in him;5but whoever keeps His word, in him the love of God has truly been perfected. By this we know that we are in Him:
13I am writing to you, fathers, because you know Him who has been from the beginning. I am writing to you, young men, because you have overcome the evil one. I have written to you, children, because you know the Father.14I have written to you, fathers, because you know Him who has been from the beginning. I have written to you, young men, because you are strong, and the word of God abides in you, and you have overcome the evil one.
6We are from God; he who knows God listens to us; he who is not from God does not listen to us. By this we know the spirit of truth and the spirit of error.7Beloved, let us love one another, for love is from God; and everyone who loves is born of God and knows God.8The one who does not love does not know God, for God is love.
20And we know that the Son of God has come, and has given us understanding so that we may know Him who is true; and we are in Him who is true, in His Son Jesus Christ. This is the true God and eternal life.