His question seems innocent enough but reflects an intra-Jewish debate on how to rank and/or summarize all of the scriptural commandments and on whether such ranking is in fact possible at all (cf., e.g., m. Hag. 1:8; b. Ber. 63a; Mek. 6). Moreover, given Jesus’ radical views on the law, an open-ended question such as this would surely elicit some remark by which Jesus would indict himself.

Neither form of the text implies a compartmentalization of the human psyche. Rather, both refer to wholehearted devotion to God with every aspect of one’s being, from whatever angle one chooses to consider it—emotionally, volitionally, or cognitively. This kind of “love” for God will then result in obedience to all he has commanded (cf. Deut 6:1–3, 6–9).

Jewish interpreters had long recognized the preeminent value of each of these laws; Jesus apparently was the first to fuse the two and to exalt them above the whole law (though Philo, Spec. Leg. 2:15, comes close to doing this).

These two commandments are the greatest because all others flow from them; indeed the whole Old Testament “hangs” on them. In other words, all other commandments are summed up and/or contained in these.

The relationship of all the Old Testament to the double love commandment shows that there is a hierarchy of law that above all requires one’s heart attitude to be correct. If this is absent, obedience to commandments degenerates into mere legalism.