Leviticus 19:1 to 20:27, Amos 9:7-15 and Ezekiel 20:2-20
"And you shall love your neighbor as yourself" (19:18). M. Scott Peck writes in People of the Lie, "I cannot be any more specific about the methodology of love than to quote these words of an old priest who spent many years in the battle: 'There are dozens of ways to deal with evil and several ways to conquer it. All of them are facets of the truth that the only ultimate way to conquer evil is to let it be smothered within a willing, living human being. When it is absorbed there like blood in a sponge or a spear into one's heart, it loses its power and goes no further.'"
The Hebrew word for "circumcised" is the same word as "pruned". Just like fruit trees, the Israelites males were "pruned" to produce "better fruit". The Israelites hearing the command of verse 19:23-24 would have this metaphor in mind, as well as the story of Gan Eden, as they are told that a young tree (unpruned in its first three years) is forbidden and if they can resist eating from in then in the fourth year the fruit becomes kodesh hilulim ("holy for giving praise").
After verse 19:18 says to love our neighbor as ourself, verses 19:33-34 repeat this for a neighbor who is a geyr. The community is divided into two categories, geyr and ezrach (see Exodus 12:19 and Leviticus 24:16), normally translated foreign-born and native-born. But the issue is one of lineage, not birthplace, as verse 19:34 makes evident when it reminds the Israelites that they were all gayreem in Egypt. The community as a whole is called the edah. Adult ezrach males constitute the kahal ("the assembly", see Numbers 15:15, Joshua 8:35, Second Chronicles 30:25, 31:18).
The phrases kahal amim or kahal goyim in Genesis 28:3, 35:11, and 48:4 are sometimes interpreted to foreshadow a "spiritual Israel" that is an "assembly of peoples". This is often because of a traditional mistranslation in Ephesians 2:12 of a "commonwealth of nations". More correctly, scripture does talk about a global ekklesia but nowhere calls it "Israel"; the above verses from Genesis are fulfilled just as well when Israel because a numerous people composed of many tribes, each with its own territory.
Verses 20:1-5 discuss how God is so against sacrificing children to idolatry that people who do this will personally feel his wrath. Recall this is the reason Israel was to kill those in the Land (Genesis 15:16, Leviticus 20:23).
When verse 19:3 says that "a man shall fear his mother and father" the mother is mentioned first since people more naturally fear their fathers. Similarly, in Exodus 20:12 it says "honor your father and mother" with the father mentioned first since people most naturally honor their mothers.
Verse 20:12 prohibits adultery with "the wife of a man... the wife of a friend". This repetition shows that if someone commits adultery with your wife, you are just as guilty if you try to seduce their wife in revenge.
The Gemara personalizes the evil inclination when discussing this Parasha: "The person who is the greater among his friends, him the evil inclination bothers more. He need not bother with the wicked, who have long been obedient to him, and for them he does not have to put in a great deal of work."
If an animal that brings evil to men without understanding its crime is killed (verse 20:15), how much more should we fear God and avoid intentional sins!
In verse 20:17, we read that if a man seduces his sister it is evil and punishable, but also "merciful it is" (chesed hee). In what way is such a thing merciful? God is referring to the sons of Adam, who were allowed to wed their sisters even though this is normally not right, becuase there were no alternatives.
In verse 20:21 we read that if a man seduces his brother's wife it is an impurity similar to menstrual impurity. In what way is it similar? Both states have a natural end: a woman is ritually pure after the time of her "state of blood" is complete, and a childless widow is permitted to provide a child for her dead husband by his childless brother (Deuteronomy 25:5).