In this passage, Jesus summarizes the Ten Commandment law written by His own finger on stone at Sinai. The first four of the Ten Commandments focus on how to demonstrate our love for God (Deuteronomy 6:5) and the last six show how to love our neighbor (Leviticus 19:18). Jesus “fulfilled the law” by demonstrating through His earthly life how we can love God as well as our neighbor through living out the Ten Commandments. JTL18 7.1
Interestingly, rabbinical tradition taught that wherever two commandments conflicted, obedience to the greater would release the person from obeying the lesser. In contrast, Jesus held to no hierarchy within the law. It is as important to keep the Sabbath (Exodus 20:8-11) as it is to refrain from murder (Exodus 20:13). It is as important to love our neighbor—even the outcast and the foreigner—as it is to love God. JTL18 7.2
Such an encompassing love that requires from us heart, spirit, and mind—indeed, total submission—can only be carried out through the power of Christ living in us. JTL18 7.3