The setting is a Pharisee's dinner table, and the host “marvelled that he had not first washed before dinner”: netilat yadayim, the ritual hand-pouring before bread (explained in this site's Mark 7 note). Jesus answers with the tradition's own vocabulary of vessels: “Now do ye Pharisees make clean the outside of the cup and the platter.” The purity law genuinely distinguished a vessel's outside from its inside; the Mishnah's tractate on vessels opens a chapter with exactly that: “All vessels have different laws for their outer and inner sides” (Kelim 25:1). Jesus turns the technical distinction into a mirror: the inside of the person is the part that counts.

Luke's tithing woe is sharper than Matthew's, and knowing the law shows why: “ye tithe mint and rue and all manner of herbs.” The Mishnah exempts rue from tithes (Sheviit 9:1 lists it first among the exempt plants). The Pharisees of the woe are tithing beyond what even their own tradition required, while “judgment and the love of God” go passed over. As in Matthew 23:23, Jesus affirms the scruple (“these ought ye to have done”) and indicts the inversion of weight.