He who touches the dead body of any human being shall be unclean seven days.
Torah Temimah: Avodah Zarah 37b — Elsewhere it says (v. 22) “and whatever the unclean person touches shall be unclean, and the person who touches it shall be unclean until evening.” How is this resolved? By Torah law, one who touches [the corpse] is unclean [seven days], and one who touches one who touched is clean [after evening].
English: By Torah law, one who touches [the corpse] is unclean, and one who touches one who touched is clean [after evening].
Resolution of the apparent contradiction between seven-day and evening impurity.
Direct contact with a corpse produces seven-day impurity; contact with a person who touched a corpse produces only evening impurity.