Deuteronomy 4:42

that a manslayer might flee there, who unintentionally slew his neighbor without having enmity toward him in time past; and by fleeing to one of these cities he might live:

Numbers 35:6

The cities which you shall give to the Levites shall be the six cities of refuge, which you shall give for the manslayer to flee to; and in addition to them you shall give forty-two cities.

Numbers 35:11-12

then you shall select for yourselves cities to be your cities of refuge, that the manslayer who has killed any person unintentionally may flee there.

Numbers 35:15-28

These six cities shall be for refuge for the sons of Israel, and for the alien and for the sojourner among them; that anyone who kills a person unintentionally may flee there.

Deuteronomy 19:1-10

When the Lord your God cuts off the nations, whose land the Lord your God gives you, and you dispossess them and settle in their cities and in their houses,

Hebrews 6:18

so that by two unchangeable things in which it is impossible for God to lie, we who have taken refuge would have strong encouragement to take hold of the hope set before us.

Treasury of Scripture Knowledge

Summary

That the slayer might flee thither, which should kill his neighbour unawares, and hated him not in times past; and that fleeing unto one of these cities he might live:

Bible References

General references

Deuteronomy 19:1
When the Lord your God cuts off the nations, whose land the Lord your God gives you, and you dispossess them and settle in their cities and in their houses,
Numbers 35:6
The cities which you shall give to the Levites shall be the six cities of refuge, which you shall give for the manslayer to flee to; and in addition to them you shall give forty-two cities.
Hebrews 6:18
so that by two unchangeable things in which it is impossible for God to lie, we who have taken refuge would have strong encouragement to take hold of the hope set before us.