Rashi on Numbers 5:8/רש"י על במדבר ה׳:ח׳

1ואם אין לאיש גאל BUT IF THE MAN HAS NO KINSMAN — This means that the claimant who put him to the oath, died and has left no heirs,

2להשיב האשם אליו TO WHOM THAT WHEREIN HE IS GUILTY COULD BE RESTORED, when he decided at a later period to confess his sin. — Our Rabbis asked (Sifrei Bamidbar 4:1; Bava Kamma 109a): But can you find anyone in Israel who has no kinsman whatsoever, neither a son nor a brother nor other relative near akin to him from his father’s family, going back as far as Jacob? But this person referred to is a proselyte who died and has no heirs (his heathen relatives not being entitled to succeed to his property) (Sifrei Bamidbar 4:1; Bava Kamma 109a).

3האשם המושב THAT WHEREIN HE IS GUILTY AND WHICH HATH TO BE RESTORED — i.e. the principal (האשם) and the fifth thereof (המושב) (cf. Bava Kamma 110a),

4לה’ לכהן BELONGS TO THE LORD, FOR THE PRIEST — This means the Lord becomes its owner and gives it to the priest of that Mishmar (shift) (Bava Kamma 109b).

5מלבד איל הכפרים BESIDES THE RAM OF EXPIATION which is mentioned in the Sedrah ויקרא (Leviticus 5:25), as being incumbent upon him to offer.