Here "walk according to" is a metaphor for "obey." The Pharisees and scribes asked this question to challenge Jesus's authority. This can be written as a statement. Alternate translation: "Your disciples should not disobey the traditions of our elders by eating their bread with unclean hands." (See: [[rc://en/ta/man/jit/figs-rquestion]] and [[rc://en/ta/man/jit/figs-metaphor]])
# unclean
The hands were ritually unclean because the disciples had not performed the ceremonial washing. The Pharisees were not accusing them of eating with physical dirt on their hands.