Deuteronomy 4:42

that the manslayer might flee thither, that slayeth his neighbor unawares, and hated him not in time past; and that fleeing unto one of these cities he might live:

Numbers 35:6

And the cities which ye shall give unto the Levites, they shall be the six cities of refuge, which ye shall give for the manslayer to flee unto: and besides them ye shall give forty and two cities.

Numbers 35:11-12

then ye shall appoint you cities to be cities of refuge for you, that the manslayer that killeth any person unwittingly may flee thither.

Numbers 35:15-28

For the children of Israel, and for the stranger and for the sojourner among them, shall these six cities be for refuge; that every one that killeth any person unwittingly may flee thither.

Deuteronomy 19:1-10

When Jehovah thy God shall cut off the nations, whose land Jehovah thy God giveth thee, and thou succeedest them, and dwellest in their cities, and in their houses;

Hebrews 6:18

that by two immutable things, in which it is impossible for God to lie, we may have a strong encouragement, who have fled for refuge to lay 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 Jehovah thy God shall cut off the nations, whose land Jehovah thy God giveth thee, and thou succeedest them, and dwellest in their cities, and in their houses;
Numbers 35:6
And the cities which ye shall give unto the Levites, they shall be the six cities of refuge, which ye shall give for the manslayer to flee unto: and besides them ye shall give forty and two cities.
Hebrews 6:18
that by two immutable things, in which it is impossible for God to lie, we may have a strong encouragement, who have fled for refuge to lay hold of the hope set before us:

American Standard Version Public Domain