What does Mark 12:30 mean?

"Love" here doesn't just mean to have affections for. It is from the Greek root word agapao, which many are more familiar with through the noun agape. To agape-love someone is a choice. It is to choose to see them in a favorable light. To choose to delight in them. And to choose to faithfully act on their behalf. When we agape-love God, we see Him as honorable, true, and loving. We trust Him and respond to that trust with obedience.

Jesus adds more nuance to this love. "Heart" is from the Greek root word kardia, and means the center of one's life, whether physical, spiritual, or mental. The heart drives one's beliefs, emotions, thoughts, and intentions. "Soul" is from the Greek root word psychē which is similar to the heart, but focuses on the vital force that keeps us alive. "Mind" is not found in the original Old Testament quote (Deuteronomy 6:5), but is certainly appropriate to add for an audience influenced by more logical Greek culture. It comes from the Greek root word dianoia and, again, has a similar definition to heart but with a more mental bent.

So, "heart…soul…and mind" cover every aspect of our personalities, being, and thoughts, and everything which influences our feelings, beliefs, desires, and intentions.

"Strength" is a little different. It is from the Greek root word ischyos, and means force, power, and ability. The original Hebrew is from the root word me'ōde, which is also translated as "greatly, exceedingly, and diligently." This "strength," also translated into English as "might," is the effort and passion with which we love God. Where the heart, soul, and mind direct how we feel and what we do, might is the force that determines the extent.

We're not exactly sure of the scribe's intent, here. Unlike the previous two challenges, there's no clear "trap" involved (Mark 12:13). He might simply be asking a deliberately provocative question, expecting Jesus to pick one of the many commandments in the Mosaic law and declare it the greatest. What Jesus has done is give a commandment that encompasses the first four of the Ten Commandments, all of which concern how we interact with God. In the third part of Jesus' answer, to love our neighbors as ourselves, He brings in the last six of the Ten Commandments. In doing so, He reveals that God's laws are not meant to control us, they are meant to describe what it means to love.