This is how we know that we know him: if we keep his commandments.
The advocate is the intercessor, the one who intercedes for you. One who is representing you, one who stands there in your behalf, one who pleads your case or your cause. If we sin, we have Jesus up there as our advocate before the Father, Jesus Christ the righteous. "Therefore, He is able to save to the uttermost all who will come unto God by Him, seeing He ever liveth to make intercession for them" ( Hebrews 7:25 ). Paul in Romans 8:0 tells us, "Who is He that condemneth, it is Christ who died, yea rather is risen again, and is even at the right hand of the Father making intercession for us." Writing to Timothy, he said, "There is one God and one mediator between God and man, the man Christ Jesus." So, when we sin, we have an advocate with the Father, one who is representing us, even Jesus Christ the Righteous.