be hidden: i.e. if he forget his uncleanness. This clause "and if", &c, is omitted in the Septuagint and included in Leviticus 5:3.
Related Commentaries of Leviticus 5:2
Leviticus 5:2
2 Or if a soul touch any unclean thing, whether it be a carcase of an unclean beast, or a carcase of unclean cattle, or the carcase of unclean creeping things, and if it be hidden from him; he also shall be unclean, and guilty.