Matthew Henry on Joshua 20:1-6

When the Israelites were settled in their promised inheritance, they were reminded to set apart the cities of refuge, whose use and typical meaning have been explained, Nu 35; De 19. God's spiritual Israel have, and shall have in Christ and heaven, not only rest to repose in, but refuge to secure themselves in. These cities were designed to typify the relief which the gospel provides for penitent sinners, and their protection from the curse of the law and the wrath of God, in our Lord Jesus, to whom believers flee for refuge, Heb 6:18.