according to the foreknowledge of God the Father, in sanctification of the Spirit, that you may obey Jesus Christ and be sprinkled in his blood: Grace to you and peace be multiplied.
through sanctification of the Spirit: Peter here gives the second criteria of election. He first says we are elect "according to the foreknowledge of God," and now he says our election is "through sanctification of the Spirit." "Sanctification" means "to set apart, to consecrate." All members of the Godhead are involved in this matter of salvation: God provides the "set purpose," the plan for man’s salvation; the Holy Spirit separates the sinner from the sphere where he dwelt in his sins to the sphere where the elected ones are; and Christ provides the cleansing for man through His own precious blood.