Albert Barnes Commentary Matthew 23:27

"Woe unto you, scribes and Pharisees, hypocrites! for ye are like unto whited sepulchres, which outwardly appear beautiful, but inwardly are full of dead men`s bones, and of all uncleanness." — Matthew 23:27 (ASV)

Like unto whited sepulchres. For the construction of sepulchres, see Barnes on Matthew 8:28.

Those tombs were annually whitewashed to prevent the people from accidentally coming into contact with them as they went up to Jerusalem. The law considered those persons unclean who had touched anything belonging to the dead (Numbers 19:16). Sepulchres were therefore often whitewashed so that they might be distinctly seen.

Thus "whited," they appeared beautiful, but within they contained the bones and corrupting bodies of the dead. So the Pharisees. Their outward conduct appeared well, but their hearts were full of hypocrisy, envy, pride, lust, and malice—fitly represented by the corruption within a whited tomb.