Matthew 23:27

"Alas for you, Scribes and Pharisees, hypocrites, for you are just like whitewashed sepulchres, the outside of which pleases the eye, though inside they are full of dead men's bones and of all that is unclean.

Luke 11:44

Alas for you! for you are like the tombs which lie hidden, and the people who walk over them are not aware of their existence."

Treasury of Scripture Knowledge

Summary

And whosoever toucheth one that is slain with a sword in the open fields, or a dead body, or a bone of a man, or a grave, shall be unclean seven days.

Bible References

A grave

Matthew 23:27
"Alas for you, Scribes and Pharisees, hypocrites, for you are just like whitewashed sepulchres, the outside of which pleases the eye, though inside they are full of dead men's bones and of all that is unclean.
Luke 11:44
Alas for you! for you are like the tombs which lie hidden, and the people who walk over them are not aware of their existence."