Answer:
Commandments one through four (of the 10 commandments - Exodus 20:3-11) are about how we are to act toward God. And the remaining six deal with how act toward each other (Exodus 20:12-17).
So the first great commandment: "You shall love the LORD your God with all your heart, with all your soul, and with all your mind" (MT 22:37), covers the first four.
And the second great commandment: "You shall love your neighbor as yourself" (MT 22:39), covers the last six. It's all about showing love.