Moses instructed the Israelites that after God delivered the land from the nations, they were to divide their land into three sections by roads. In each section, they were to establish a city of refuge. A manslayer could flee there. If a manslayer killed his neighbor unintentionally, without premeditation, he can flee to one of these cities and live. The avenger of blood could not touch him there. If the Lord were to expand their territory, which He promised to give their fathers, then they would designate three additional cities of refuge.
There was a distinction made between unintentional killing and premeditated killing, however. Anyone who kills his neighbor by design will not find refuge in the cities. Instead, the elders of those cities would deliver them back to the avenger.
They were additionally warned not to move ancient landmarks, but to honor the property boundaries in the promised land.
It is important to discern the intent of one’s heart. What is the motivation for any action? We may do some things that are sinful on their surface, but are not intended or prethought. However, intentional sin carries a heavier weight of guilt. While sin is sin, it is important to look upon the intention of the heart. Avoid all sin, but do not intentionally transgress the commandments of God for sure!