Numbers 35:12

The avenger. From a word whose root generally means “to redeem,” “to act as a kinsman,” implying close personal relationship. The duties of this “kinsman-redeemer” became both varied and many. One of his duties was to avenge a relative’s murder. He was also to contract a levirate marriage (Ruth 3:13), to purchase a kinsman from slavery into which unfortunate circumstances had forced him (Lev. 25:47, 48), to prevent the alienation of family property (Jer. 32:8-12), and to buy back such property as may have fallen into the hands of others (Lev. 25:25).

Stand before the congregation. Just what duties the congregation performed is not stated in detail. But undoubtedly the whole procedure was forensic, with presentation of evidence, discussion, and decision by jury (see Num. 27:2; Deut. 19:17; Joshua 20:6). Note that Deut. 19:12 has the expression “the elders of his city.”