God's law is the definition of love and God's law also tells us much about God and His justice.  God's law is the definition of justice.  Those who argue with this must consider that the all-knowing, all-wise God may just be more intelligent than the creature that God created.  For some egos, that may be a difficult concept to comprehend.

These commands, don't pervert marriage, kill, steal, or lie, don't want what someone else has or be mad that they have it--or any other commandment, is simple to understand: love thy neighbour.

For this, Thou shalt not commit adultery (Any Perversion Of Marriage Including Fornication, Sensuality, and Any Other Such Perversion), Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false witness, Thou shalt not covet; and if there be any other commandment, it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself.