Why does Christ cleanse the church with the Word?
Christ cleanses the church with the Word, not water, to purify the spiritual body and keep it in service. This prepares the church to be presented to Himself as glorious, without spot, wrinkle, or blemish—holy and blameless. The cleansing motivates believers to walk carefully, not carelessly, and to glorify His name.
Les explains that rather than water, the spiritual body is cleansed by the Word of God, and this is what keeps believers in a place of service. The purpose is that Christ might present the church to Himself as a glorious body, not having spot or wrinkle or any such thing, but holy and without blemish. Les says this is the whole concept of walking the Christian life: believers are not to be careless or take the attitude, 'I'm saved, so what?' Instead, their constant desire should be to bring glory to His name. He illustrates this with the Heidelberg Catechism's first question—what is the chief end of man?—to glorify God and enjoy Him forever.