I like this verse because it promotes holiness and righteousness in the life of Christians. I tells without confusions that if we obey God's Word that we can be sure that we know The Holy and Living God!
There is a second verse among many that states: If you Love me (Jesus) you will obey my commandments.
To often Christians lose sight of their calling to Holiness and purity in Jesus Christ and become just as the world in their speech and actions. As the children of God we are called to be pure in His sight, spotless and white as snow, and a light unto the dark places. The Word of God says that we must abstain from sin, to abstain is to abhor or hate sin, to flee or run from it. The Bible says that our sin separates us from a Holy God. To separate is to build a wall or to be without... to be separate from God is to be dead spiritually.
Obey the Word of God and Love Him...