1 John 3:23-24
This is His commandment, that we believe in the name of His Son Jesus Christ, and love one another, just as He commanded us. The one who keeps His commandments abides in Him, and He in him. We know by this that He abides in us, by the Spirit whom He has given us.
The Commandments
It would be easy to mistakenly interpret the keeping of the "commandments" in the previous verses to be referring to some legal system, whether that of the Law of Moses, or some other legalistic system that modern man would contrive. However, John safeguards the reader against such wrong understanding by laying out the clear commandments of The Lord, just as it is preserved in John 13:34.
Command #1: Believe in the name of His Son Jesus Christ
This is the same exhortation we would give someone asking how to be saved. Trusting in The Lord Jesus Christ and His work on our behalf is not just the chief characteristic of the Gospel of Grace, it is also the chief characteristic of the believer who is walking with Jesus Christ every moment of every day. Our faith in Jesus Christ is exactly what The Lord has for us with each passing moment. Trusting Him, and Him alone, for our salvation, sanctification, keeping and ultimate gathering unto Himself.
Command #2: Love one another
This is the thing we are finally freed to do based on our trust in Jesus Christ. With His limitless supply of love available to us we begin to long for objects whom we can lavish that love upon, just as He lavished it upon us. When this is not our experience in our daily experience we can be sure that we have looked away from trusting in Christ as the source of that love. We have allowed ourselves to take our eyes off Jesus, and just like Peter when he walked on water, we begin to sink. The answer? Return our gaze to The Lord!