washed I thee - as brides used to pass through a preparatory purification (Est 2:12). So Israel, before the giving of the law at Sinai (Exo 19:14); “Moses sanctified the people, and they washed their clothes.” So believers (1Co 6:11).
oil - emblem of the Levitical priesthood, the type of Messiah (Psa 45:7).