Why does Jesus not quote the whole scripture?

Mark 12:28-34

28 One of the scribes came near and heard them disputing with one another, and seeing that he answered them well, he asked him, “Which commandment is the first of all?” 29 Jesus answered, “The first is, ‘Hear, O Israel: the Lord our God, the Lord is one; 30 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.’ 31 The second is this, ‘You shall love your neighbor as yourself.’ There is no other commandment greater than these.” 32 Then the scribe said to him, “You are right, Teacher; you have truly said that ‘he is one, and besides him there is no other’; 33 and ‘to love him with all the heart, and with all the understanding, and with all the strength,’ and ‘to love one’s neighbor as oneself,’ —this is much more important than all whole burnt offerings and sacrifices.” 34 When Jesus saw that he answered wisely, he said to him, “You are not far from the kingdom of God.” After that no one dared to ask him any question.

The first commandment that Jesus quotes is the Shema of the Jewish tradition from Deuteronomy 6:4. The second commandment (underlined) is from Leviticus 19:18, but Jesus does not say the entire scripture.

Why?

Here is the entire verse - "You shall not take vengeance or bear a grudge against any of your people, but you shall love your neighbor as yourself: I am the Lord."

Why does Jesus not cite the first half of this verse? 

What does it mean for us to understand the "golden rule" without the "take no vengeance" part? 

It seems that we all know that we should love one another. But the fact of the matter is that one person's act of love is another's act of hate. (Also see the language of some people who discuss the future of this country) 

Have we overlooked to basics of what love looks like? At the very basic level love is without vengeance and grudges. 

Liberals who watch FOXNews - uncomfortable on purpose

Scripture is often a source of great comfort for many people. When there is a funeral you can but there will be a reading from Psalm 23. When you hear 1 Corinthians 13 is read, 93.6% of the time you are at a wedding. When there is tragedy in real life or in a play, you can find scripture be a source of strength and comfort.

In the same breath, scripture is also the source of great discomfort. When Jesus tells the people to sell all they have and give it to the poor. When we read about God destroying people and nations. Where there is a difficult teaching for which there is no simple answer, you can find scripture to be a source of discomfort.

We watch the news to be comforted. This is why conservatives will watch FOXNews and liberals watch MSNBC. We watch the news in order to hear others tell us that our worldview is correct. We love to hear our side is correct and the other side is wrong and idiotic.

For many Christians, we tend to read scripture like we watch the news. We choose the places that we like that affirm our worldview. We choose the places that provide us comfort and provide discomfort for others. We choose our own canon which we feel is "truer" or "more in line with God" than other scripture.

Do yourself and the world a favor - read the discomforting scripture. Watch the "other" news channel. Allow for the possibility that you may be wrong. The irony is that by listening to only the sources that bring us comfort, we actually harden our hearts through the phenomena of expectation confirmation.

What is true learning? Not addition.

A church person once told me that they attend church in order to learn more and "grow in their faith". When pressed on what they mean when they say "grown in their faith" this church person said to grow in faith is to be built up in the grace and knowledge of Christ.

Like creativity, growing in Christ is about subtraction.

That sounds like a great church answer. 

Of course we are looking to be shaped in the ways of Christ. But let us address something that maybe we know but forget.

Learning is not about addition↬. It is a common understanding that when we learn it is like just filling up a container (our brain) with more information and data. This is a big reason we want our children to go to college, so they can learn "more" because there is a sense of lack without that education. 

If you have attended any level of education and reflect on your experience, it is clear that leaning is about subtraction rather than addition. 

We do not come to school with a lack but with an abundance of "what we know to be true" and the challenge of education is that it asks us to not add to "what we know to be true" but calls into question "what we know to be true". Learning is, at its core, about subtraction. 

When we attend church, and if we are there to grow in the knowledge and grace of Christ, then we must be reorient ourselves away from addition and toward subtraction or (ironically) we will never grow.

*On a separate note, this is post #800!