Thematic Bible: Summed up by Christ

And one of their number, a lawyer, asked Him a question to test Him. Teacher, which kind of commandment is great and important (the principal kind) in the Law? [Some commandments are light -- "which are heavy?] And He replied to him, You shall love the Lord your God with all your heart and with all your soul and with all your mind (intellect). read more.
This is the great (most important, principal) and first commandment. And a second is like it: You shall love your neighbor as [you do] yourself. These two commandments sum up and upon them depend all the Law and the Prophets.