The text of today contains the sixth (23,27-28) and seventh (23,29–36) woes begun in 23,13. The sixth Woe concerns “whitewashed tombs”. As a public service, tombs were whitewashed to make them more obvious, since contact with the dead and with graves, even if unintentional, transmitted ritual impurity (Num 19,11-22). This was especially important to pilgrims at Passover time, who would not know the places they visited. The point that Matthew makes is “ostentatious exterior, corrupt interior”. The seventh and final Woe extends the tomb image and modulates into the concluding theme: The rejection of the prophets God has sent.
The challenge then to each one of us is to bother less about what we ought to do and think more about what we ought to be, because if our being were good then our works would shine forth brightly.