Deuteronomy 4:42

And among the cities which ye shall give unto the Levites there shall be six cities for refuge, which ye shall appoint for the manslayer, that he may flee thither: and to them ye shall add forty and two cities. So all the cities which ye shall give to the Levites shall be forty and eight cities: them shall ye give with their suburbs. And the cities which ye shall give shall be of the possession of the children of Israel: from them that have many ye shall give many; but from them that have few ye shall give few: every one shall give of his cities unto the Levites according to his inheritance which he inheriteth. And the LORD spake unto Moses, saying, Speak unto the children of Israel, and say unto them, When ye be come over Jordan into the land of Canaan; Then ye shall appoint you cities to be cities of refuge for you; that the slayer may flee thither, which killeth any person at unawares. And they shall be unto you cities for refuge from the avenger; that the manslayer die not, until he stand before the congregation in judgment. And of these cities which ye shall give six cities shall ye have for refuge. Ye shall give three cities on this side Jordan, and three cities shall ye give in the land of Canaan, which shall be cities of refuge. These six cities shall be a refuge, both for the children of Israel, and for the stranger, and for the sojourner among them: that every one that killeth any person unawares may flee thither. And if he smite him with an instrument of iron, so that he die, he is a murderer: the murderer shall surely be put to death. And if he smite him with throwing a stone, wherewith he may die, and he die, he is a murderer: the murderer shall surely be put to death. Or if he smite him with an hand weapon of wood, wherewith he may die, and he die, he is a murderer: the murderer shall surely be put to death. The revenger of blood himself shall slay the murderer: when he meeteth him, he shall slay him. But if he thrust him of hatred, or hurl at him by laying of wait, that he die; Or in enmity smite him with his hand, that he die: he that smote him shall surely be put to death; for he is a murderer: the revenger of blood shall slay the murderer, when he meeteth him. But if he thrust him suddenly without enmity, or have cast upon him any thing without laying of wait, Or with any stone, wherewith a man may die, seeing him not, and cast it upon him, that he die, and was not his enemy, neither sought his harm: Then the congregation shall judge between the slayer and the revenger of blood according to these judgments: And the congregation shall deliver the slayer out of the hand of the revenger of blood, and the congregation shall restore him to the city of his refuge, whither he was fled: and he shall abide in it unto the death of the high priest, which was anointed with the holy oil. But if the slayer shall at any time come without the border of the city of his refuge, whither he was fled; And the revenger of blood find him without the borders of the city of his refuge, and the revenger of blood kill the slayer; he shall not be guilty of blood: Because he should have remained in the city of his refuge until the death of the high priest: but after the death of the high priest the slayer shall return into the land of his possession.

When the LORD thy God hath cut off the nations, whose land the LORD thy God giveth thee, and thou succeedest them, and dwellest in their cities, and in their houses; Thou shalt separate three cities for thee in the midst of thy land, which the LORD thy God giveth thee to possess it. Thou shalt prepare thee a way, and divide the coasts of thy land, which the LORD thy God giveth thee to inherit, into three parts, that every slayer may flee thither. And this is the case of the slayer, which shall flee thither, that he may live: Whoso killeth his neighbor ignorantly, whom he hated not in time past; As when a man goeth into the wood with his neighbor to hew wood, and his hand fetcheth a stroke with the axe to cut down the tree, and the head slippeth from the helve, and lighteth upon his neighbor, that he die; he shall flee unto one of those cities, and live: Lest the avenger of the blood pursue the slayer, while his heart is hot, and overtake him, because the way is long, and slay him; whereas he was not worthy of death, inasmuch as he hated him not in time past. Wherefore I command thee, saying, Thou shalt separate three cities for thee. And if the LORD thy God enlarge thy coast, as he hath sworn unto thy fathers, and give thee all the land which he promised to give unto thy fathers; If thou shalt keep all these commandments to do them, which I command thee this day, to love the LORD thy God, and to walk ever in his ways; then shalt thou add three cities more for thee, beside these three: That innocent blood be not shed in thy land, which the LORD thy God giveth thee for an inheritance, and so blood be upon thee.

That by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us: