In the books of Moses we find many laws and institutions that had a practical application under the old covenant, but that also, and above all, point forward to something better. The law is the introduction of a better hope (Heb.7:19). The things we find described in the law are therefore only an example and shadow and point us to heavenly things (Heb.8:5; 10:1).
cities of refuge
It is the same with the cities of refuge. The law of Moses stipulated that there would be six cities of refuge in the land of Canaan: three west of the Jordan and three east of the Jordan (Josh.20:2, 7-8). If one of the people had killed his brother unintentionally, he could flee to one of these cities of refuge and be safe from the avenger of blood. We find this described, for example, in:
Deuteronomy 19
4 In the following case, the manslayer who flees there will live: if he kills his neighbour without intent, although he had no hatred against him before.
5 For example, if a man goes into the woods with his neighbour to cut wood, and his hand swings an ax to fell a tree, and the iron falls off the handle and strikes his neighbour and he dies, he can flee to one of those cities and stay alive.
ignorance
The manslayer who had ignorantly killed his neighbour would be safe in the city of refuge from the vengeance of the avenger of blood (Num.35:12). Outside the city of refuge he was not (Num.35:26-28). The manslayer would not have to stay in the city of refuge forever. He would be allowed to go wherever he wanted again after the death of the high priest.
Numbers 35
28 For he shall dwell in the city of refuge until the death of the high priest, and after the death of the high priest the manslayer shall return to the land of his possession.
the Jewish people and the ecclesia
This manslayer and the city of refuge are a wonderful type of the Jewish people who killed their brother, Jesus Christ. They did this in ignorance and that is why the Lord also prayed on the cross: “Father, forgive them, for they know not what they do.” (Luke 23:34). Even after His resurrection, the disciples declare to the Jewish people that they have acted in ignorance.
Acts 3
17 And now, brethren, I know that you have done it through ignorance, as also your rulers.
This was not held against the Jewish people who had crucified their Messiah in ignorance. They can flee to the city of refuge, an image of the eccclesia, the body of Christ. When the high priest of those days dies (Josh.20:6), a picture of the ending of the old covenant, a new covenant will dawn for them and the people will return to the land of Israel (Num.35:28).