One of the scribes came to Jesus and asked him,
"Which is the first of all the commandments?"
Jesus replied, "The first is this:
You shall love the Lord your God with all your heart, with all your soul,
with all your mind, and with all your strength.
The second is this:
You shall love your neighbor as yourself.
There is no other commandment greater than these." (Mk 12:28b-34)
The trick question about the greatest commandment is answered with Jesus linking love of God with love of neighbor, and saying they are the same thing. And we have been struggling with this teaching ever since.