Deuteronomy 19:3
Thou shalt prepare thee a way, and divide the coasts of thy land, which the LORD thy God giveth thee to inherit, into three parts, that every slayer may flee thither. Thou shalt prepare thee a way, and divide the coasts of thy land, which the LORD thy God giveth thee to inherit, into three parts, that every slayer may flee thither.
The inherited land was to be divided into three districts with prepared routes so that any person who had taken life could flee to a city of refuge. Those roads were to be clearly marked and clearly laid out, divided and kept clear so that one fleeing for life would meet no obstruction or hindrance. That clearly marked way to refuge pictures how clearly defined is the way to happiness and life, which is marked out by loving obedience to God. By contrast, the way of disobedience leads to misery.
Keeping that way of safety open and accessible is a binding duty, and Israel's religious teachers failed in the corresponding duty to keep the way of life and righteousness clear, instead misleading those who were seeking the kingdom of heaven.