Luke 12:1 warns against the leaven of Pharisees, i.e., hypocrisy — the same hidden corruption as unmarked graves.

Numbers 19:16 establishes that touching a grave causes uncleanness—the law Jesus alludes to when calling Pharisees unmarked graves.

Matthew 23:27 uses the same tomb imagery—whitewashed outside, dead inside—making the metaphor explicit.

Matthew 23:28 draws the same contrast between outward righteousness and inner hypocrisy from the tomb metaphor.

Leviticus 5:2 establishes impurity from touching graves, the OT law underlying Jesus' metaphor of hidden defilement.

Psalm 5:9 uses 'open grave' for deceitful speech; Luke applies a similar grave metaphor to hidden corruption.

Ezekiel 39:15 shows marking graves to avoid defilement — contrasting with the unmarked Pharisees Jesus condemns.