From The Gospel of Mark, by Mary Healy, commenting on Mark 7:1-8, 14-15, 21-23
The third section is the climax, in which the point of the whole discussion (7:1–23) comes to light. After his lengthy criticism of the “traditions of the elders” (vv. 6–13), Jesus now goes back to answer the question about his disciples eating with unwashed hands (v. 5).
As will become clear it is no mere matter of lax discipline. So significant is the following pronouncement that Jesus summons the crowd so that all might hear it. He prefaces it with a solemn injunction that highlights the enigmatic nature of what he is about to say and the need to ponder it carefully: Hear me, all of you, and understand. He had given similar admonitions in 4:3, 9, 23, 24, but now there is a more direct emphasis on his own authority: “Hear me.” “All of you” may be to emphasize that his next pronouncement is intended not only for his immediate audience, but for all Christians in all generations.
Jesus first states his point in parable form to the crowds, before giving an explanation privately to his disciples (see 4:34). Nothing that enters from outside can defile a person. This statement broadens the discussion far beyond ritual washings or even oral traditions; it alters the status of a large portion of the Torah itself, the written law that is the foundation of Judaism. The verb “defile” is a legal term in the Torah (related to “unclean” in v. 2), meaning to render something unclean, unfit for worship of God or any sacred use. Much of the law of Moses concerns the distinction between clean and unclean, how a person or object becomes unclean, and what to do about it (see especially Lev 11–15; Deut 14).
Jesus is radically recasting the whole meaning of clean and unclean: external things cannot defile a person; rather uncleanness comes from within, from the deep inner wellspring of a person’s words and actions. Already in the Old Testament the prophets had decried merely ceremonial, external practices of devotion (see Isa 1:11–17; Hosea 6:6; Amos 5:21–27) and taught that the true defilement is evil conduct (Ezek 36:17). But Jesus is going far beyond this to set aside the whole system of ceremonial cleanness—because in him its purpose is now fulfilled.