You shall not hate your brother in your heart, but you shall reason frankly with your neighbor, lest you incur sin because of him. You shall not take vengeance or bear a grudge against the sons of your own people, but you shall love your neighbor as yourself: I am the Lord. (Vayikra / Leviticus 19:17-18; ESV)
The Messiah was asked the question, "What is the greatest commandment?" (See Matthew 22:35-40; Mark 12:28-34; Luke 10:25-37). It was popular among Jewish religious leaders to attempt to summarize the Torah. Here is Yeshua's answer:
The most important is, "Hear, O Israel: The Lord our God, the Lord is one. And you shall love the Lord your God with all your heart and with all your soul and with all your mind and with all your strength." The second is this: "You shall love your neighbor as yourself." There is no other commandment greater than these. (Mark 12:29-31; ESV)
Some people take this to mean that unlike the people living under the Old Covenant, followers of Yeshua have only these minimal requirements to follow. But that completely misses the point. Yeshua's summary statement is intended as a perspective by which to view God's requirements, not a recipe by which to ignore them. Yeshua was reminding a people who had become obsessed with the Torah as an end in itself that its directives were intended as the means of loving God and other people. Losing sight of these primary commands results in the failure to properly keep the others. Loving God and loving people is what God's commands are all about.
Hearing Yeshua highlight "You shall love your neighbor as yourself," should draw us to the context of what he was quoting, some of which we read at the beginning. Loving our neighbor is not a vague sentimental concept based on emotion. It has very practical and far reaching implications. For example we read, "You shall not hate your brother in your heart, but you shall reason frankly with your neighbor, lest you incur sin because of him." This tells us first that when difficulties arise with someone with whom we have relationship, we are not to hate them. Hate is not simply negative and angry thoughts toward another person. It is the tendency to disregard them or not care about them. This may occur with very little emotion. God instructs us that instead of ignoring issues we have with others we need to deal with them through open and honest discussion and thereby avoid even greater issues arising between one other. This is what "love your neighbor" is all about or it is at least one example.
It could be that "but you shall love your neighbor as yourself" sums up a larger Torah section (see Vayikra / Leviticus 19:9-18) that includes being mindful of the poor among us, not stealing, having fair business dealings, not lying to others, not using God's name to justify wrong, not oppressing others or robbing them, paying wages on time, showing respect toward the physically handicapped, demonstrating justice in court without partiality, not slandering, and not taking vengeance or bearing grudges against others. This is not a complete list, though it makes it clear that loving our neighbor is far more and much deeper than what we may normally think it is.
Loving our neighbor is not just having warm affection toward others or showing kindness to them, though it may include those things. God's version of loving others involves a deep understanding of his ways and how they relate to how we are to treat others. To love is to be true to our God-given responsibilities towards those with whom we have personal and work relationships, business and legal dealings, as well as the needy and vulnerable around us. Let's not cheapen God's Word by reducing it to anything less.