If we say that we have fellowship with him and walk in the darkness, we lie, and don't tell the truth.
Now over in chapter 3 verse 1Jo 1:16 , "Hereby perceive we the love of God." How can I know that God loves me? Because He laid down His life for us. You know that the Bible only seeks to prove God's love at the cross. Whenever the Bible wants to declare or to prove to you that God loves, it always points to the cross, the fact that Jesus laid down . . . "Herein is love, not that we loved God, but that He loved us and gave His Son to be the propitiation for our sins" ( 1 John 4:10 ). It always points to the cross, "God so loved the world that He gave His only begotten Son" ( John 3:16 ). Herein is love, not that we loved God, but that God loved us and sent His Son to die. So, hereby we perceive the love of God. Now, verse 1Jo 1:19 , "And hereby we know that we are of the truth." How is that? Verse 1Jo 1:18 , "Little children, let us not love in word, neither in tongue, but in deed and truth." When I am loving by my deeds, loving deeds, that's loving in truth, and by that I know that I am of the truth. Verse 1Jo 1:24 , "Hereby we know that we have abide, or that He abides in us by His Spirit that He has given us." How do I know that He is abiding in me? The Holy Spirit's indwelling my life. How can I know the truth? Verse 1 John 1:2 of chapter 4, "Hereby know we the Spirit of God." So many churches, so many religions, how can I know? "Every Spirit that confesses that Jesus Christ is come in the flesh is of God and every spirit that confesses not that Jesus Christ is come in the flesh is not of God. This is the spirit of anti-Christ." Verse 1 John 1:6 of chapter 4, "We are of God and he that knoweth God hears us; he who is not of God does not hear us. And hereby know we the spirit of truth and the spirit of error." Whether or not the person will listen to the truth. Verse 1Jo 1:13 of chapter 4, going back to verse 1Jo 1:12 , "No man has seen God at any time. If we love one another, God dwells in us, and His love is perfected in us. And hereby know we that we dwell in Him." How? Because His love is perfected in me. Then finally in chapter 5, verse 1 John 1:2 , "By this we know that we love the children of God, when we love God and keep His commandments." So, how do we know what we know? Interesting epistle, lets go back to chapter 1 and begin our study.