The revenger of blood - גאל הדם goel haddam, the redeemer of blood; the next in blood to him who was slain. See on Num 35:12 (note).

And the congregation shall deliver the slayer out of the hand of the avenger of blood,.... Put him under the care of proper persons, to conduct him to one of the cities of refuge, or put him in the way to it; and restrain the avenger of blood from pursuing him, until such time that it may be judged he is safe arrived there:

and the congregation shall restore him to the city of refuge, whither he was fled; so that it seems by this, when one had been guilty of manslaughter, and fled to one of the cities of refuge, he might be taken from thence and had before a court of justice, and there take his trial; and if it appeared that the fact was committed by him, ignorantly, unawares, and without design, then he was returned to his city of refuge; but, if otherwise, he was put to death, notwithstanding he had fled thither; and so it is said in the Misnah (t), that"at first, or formerly, one that killed another ignorantly or presumptuously, they sent him before to one of the cities of refuge, and the sanhedrim sent and fetched him from thence: he who was condemned to death by the court, they slew him; he that was not condemned was dismissed; he that was condemned to banishment they returned him to his place, according to Num 35:25."

and he shall abide in it, unto the death of the high priest, which was anointed with the holy oil: and then he was to be set at liberty, and return to his house and family and have his former possessions and honours, if he had any, restored unto him, the commission or warrant for his detainer there ceasing, being made void by the death of the high priest; who was the prince of the priests and Levites, to whom those cities belonged, and so under his jurisdiction: or so it was ordered, because such was the general mourning for such a public loss as an high priest, that all private revenges would subside, and the cause of them be buried, in grief and forgetfulness; though, no doubt, this had a respect to something which will be hereafter taken notice of: the Jews say (u), that the mothers of the priests used to supply with a sufficient quantity of food and raiment such who fled to the cities of refuge, that they might not pray for the death of their sons; and according to them, a man's case was very bad when there was no high priest; for so they write (w)"he whose cause is finished (or his case determined in a court of judicature), and there is no high priest; and he that slays an high priest, or an high priest slays another, he never goes out, no not so much as to bear testimony in any cause, and even in what the congregation has need of him, but there are his dwelling, his death, and his burial.''

(t) Misn. Maccot. c. 2. sect. 6. (u) Misn. Maccot. c. 2. sect. 3. (w) Misn. Maccot, c. 2. sect. 7.

But if he thrust him suddenly without enmity, or have cast upon him any thing without laying of wait, &c.--Under the excitement of a sudden provocation, or violent passion, an injury might be inflicted issuing in death; and for a person who had thus undesignedly committed slaughter, the Levitical cities offered the benefit of full protection. Once having reached the nearest, for one or other of them was within a day's journey of all parts of the land, he was secure. But he had to "abide in it." His confinement within its walls was a wise and salutary rule, designed to show the sanctity of human blood in God's sight, as well as to protect the manslayer himself, whose presence and intercourse in society might have provoked the passions of the deceased's relatives. But the period of his release from this confinement was not until the death of the high priest. That was a season of public affliction, when private sorrows were sunk or overlooked under a sense of the national calamity, and when the death of so eminent a servant of God naturally led all to serious consideration about their own mortality. The moment, however, that the refugee broke through the restraints of his confinement and ventured beyond the precincts of the asylum, he forfeited the privilege, and, if he was discovered by his pursuer, he might be slain with impunity.