The point Yeshua makes in Mark 7:18-23 is that ceremonial washing is not necessary for spiritual purity or sound spiritual health because unwashed hands do not defile anybody’s “heart”/spirit. It each person’s stinking thinking that spiritually defiles his or her own “heart”/spirit or mind.
Too many professed believers in Christ are resting on their laurels—are living like they are satisfied with their past achievement (salvation), so much so that they refuse to consider additional effort from them is necessary. They have assumed that their salvation automatically made them the Bride of Christ—made them saintly Overcomers. As a result, they either overlooked the Scripture that commands them to work out their own salvation, or they read and studied said Scripture but concluded it does not pertain to them.
Like the penetrating precision that surgeons make with their scalpels, Father God does the same thing with His Word. Not only does His Word cut but also it heals, after cutting along the dividing line between the soul and spirit—between human beings’ innermost parts.
The Holy Spirit’s most important goal is not only to make a believer’s BODY, SOUL, and SPIRIT one (make all three parts immortal), just like the Father, Son, and Holy Spirit are One (all three Persons are eternal); but also the Holy Spirit’s job is to make every imperfect (unholy) BODY, SOUL, and SPIRIT holy (perfect), like the Father, Son, and the Holy Spirit are HOLY (perfect)—like each of the three Persons of the Trinity is identified as being HOLY! This call to Holiness is the ONENESS reality Christ Jesus prays for in John 17:21.