6 ideas
Each law should open with a persuasive prelude explaining why the law is good, followed by the bare command and penalty. Laws with only commands treat citizens like slaves under a doctor who prescribes without explaining. Laws that also persuade treat them like free patients who are reasoned with, which wins their willing compliance.
A stable city must blend the principle of authority with the principle of liberty so that neither grows unchecked. Excess of either mother-constitution breeds its own ruin.
The Spartan and Cretan codes were designed for war and trained only courage against pain. The legislator should aim at complete virtue, with wisdom ranked first and justice, moderation, and courage following. Internal peace and reconciliation matter more than victory over outside enemies.
They also cheaply reveal a person's true character. Self-control is built by safe exposure to temptation, not only by avoidance.
Magnesia fixes its citizens at 5,040 households, a number chosen because it divides evenly by every integer from 1 to 10 and has 59 divisors in total. That makes it easy to split land, taxes, military units, and administrative duties without remainder. Fixed, equal, inalienable land lots, with wealth capped at four times the minimum, keep the political arithmetic stable.
Three beliefs threaten civic order: that gods do not exist, that they ignore human affairs, and that they can be bribed with sacrifices. The legislator should first refute these with an argument that soul is prior to matter and self-motion precedes body. Persistent unbelievers are then subject to legal penalties, supervised by a Nocturnal Council charged with preserving the law's purpose.