To "sanctify" is here to consecrate to Himself (comp. John 17:17; John 17:19) after purification. In the same connection we have in 1 Corinthians 6:11, "Ye were washed, ye were sanctified, ye were justified." In virtue of such consecration the Church visible is "holy" in idea and in capacity--the Church invisible here (which will be the Church triumphant hereafter), holy in the actual purity which becomes a consecrated nature. Of such consecration baptism is unquestionably the means; as we see in command in Matthew 28:19, and in fact in Acts 2:38; Acts 2:41.
with the washing of water; not baptism, which is never expressed by washing; nor does it purify or cleanse from sin; nor is it the means of sanctification and regeneration, which ought to be before it; nor the grace of the Spirit, though that is often compared to water, and regeneration and sanctification are owing to it; yet the saints are not so cleansed from sin by it, as to be without spot or wrinkle; but the blood of Christ, which is the fountain to wash in, and which cleanses from all sin:
by the word; not the form of words in baptism; but either the Gospel, which brings the good news and glad tidings of peace, pardon, atonement, and justification by Christ; or the sentence of justification pronounced upon the conscience by him; see John 15:2.