I find it very interesting that when Jesus was asked for the greatest commandment, He gave two commandments, not one. (Matthew 22:37-40)
Jesus replied: “’Love the Lord your God with all your heart and with all your soul and with all your mind.’
This is the first and greatest commandment.
And the second is like it: ‘Love your neighbour as yourself.’
All the law and the Prophets hang on these two commandments”. Neither of them are amongst the ten commandments.
There are a great many more commandments than the ten that are famous because of the story that surrounds them.
Notice that although Jesus quotes both, He puts a definite emphasis on the first of the two.
Notice also that the first one is expressed in a much stronger fashion than the second.
We are to love God with all of our being, whereas we are to love others merely as we love ourselves.
In the first letter of John we see the second of the two commandments follows inevitably from the first. (1 John 4:20)
If anyone says “I love God,” yet hates his brother, he is a liar. (1 John 4:8)
Whoever does not love does not know God because God is love.