2 John 1:6
And this is love, that we walk according to His commandments. This is the very commandment you have heard from the beginning, that you must walk in love.
What it says
Love means walking according to God's commandments and continuing in the command to walk in love.
What it is doing
This verse defines love in obedient, covenantal terms.
In context
4I was overjoyed to find some of your children walking in the truth, just as the Father has commanded us. 5And now I urge you, dear lady — not as a new commandment to you, but one we have had from the beginning — that we love one another. 6And this is love, that we walk according to His commandments. This is the very commandment you have heard from the beginning, that you must walk in love.