Matthew 22:34-40 / Mark 12:28-34…
And one of them, a lawyer, asked him a question to test him. This man is perhaps a little less closed minded than the rest (Mark 12:28, 32-34) but he still has an agenda. The religious leaders had believed that the teachings of Jesus were against Moses. Of course, Jesus said otherwise (Matthew 5:17). They want Jesus to say that He was giving them a law that superseded Moses, so they could charge Him as a blasphemer. In fact, they were the ones who changed the law by their traditions, while Jesus pointed to the spiritual essence of the law.
Which commandment is the most important of all? Jesus quotes Moses (Deuteronomy 6:4-5), exactly what they thought He wouldn’t do. We are called to love God with our whole being. It is more than mere belief (James 2:19), and it wasn’t something new (Nehemiah 1:5). In the light of this command, the religious leaders were hypocrites (Matthew 23:13-36).
God’s desire has always been that people would love Him fully, which results in trust and obedience. Specifically, it results in loving your neighbor as yourself. If we have this vertical love, toward God, then horizontal love, toward others, will naturally flow. If we relate to God rightly then we will relate to others rightly, and conversely if there is a problem with others we have a problem with God.
God is not saying we need to elevate our love for ourselves or for others as much as He is saying that we already love ourselves enough (Ephesians 5:29) and we should love others as much (Leviticus 19:18 / Matthew 7:12 / Galatians 5:14 / James 2:8-10 / Romans 13:8-10). This is done by loving God first. We must get the order of this right or we miss the point.
The real problem is that none of us can do this fully. However, and hallelujah, Christ has done it for us. Now, as Christians, empowered by the Holy Spirit, we can begin to fulfill this in our daily lives. The more you look to God and His love for you, the more you will live like it matters, and the more you will show it towards others.