6 Otherwise, the avenger of blood might pursue him in a rage, overtake him if the distance is too great, and kill him even though he is not deserving of death, since he did it to his neighbor without malice aforethought.
6 Lest the avenger of the blood pursue the slayer, while his heart is hot, and overtake him, because the way is long, and slay
6 lest the avenger of blood in hot anger pursue the manslayer and overtake him, because the way is long, and strike him fatally, though the man did not deserve to die, since he had not hated his neighbor in the past.
6 If the city is too far away, the avenger of blood racing in hot-blooded pursuit might catch him since it's such a long distance, and kill him even though he didn't deserve it. It wasn't his fault. There was no history of hatred between them.
6 lest the avenger of blood, while his anger is hot, pursue the manslayer and overtake him, because the way is long, and kill him, though he was not deserving of death, since he had not hated the victim in time past.
6 "If the distance to the nearest city of refuge is too far, an enraged avenger might be able to chase down and kill the person who caused the death. Then the slayer would die unfairly, since he had never shown hostility toward the person who died.
Matthew Henry's Commentary on Deuteronomy 19:6
Commentary on Deuteronomy 19:1-13
(Read Deuteronomy 19:1-13)
Here is the law settled between the blood of the murdered, and the blood of the murderer; provision is made, that the cities of refuge should be a protection, so that a man should not die for that as a crime, which was not his willing act. In Christ, the Lord our Righteousness, refuge is provided for those who by faith flee unto him. But there is no refuge in Jesus Christ for presumptuous sinners, who go on still in their trespasses. Those who flee to Christ from their sins, shall be safe in him, but not those who expect to be sheltered by him in their sins.