Trench H. Johnson, Phrases and Names, Their Origins and Meanings
“ Although this should properly be the first day of what is called Passion Week, Palm Sunday is in a sense a feast day, in allusion to the triumphant entry of Christ into Jerusalem. The Sunday previous is therefore set apart for a general commemoration of the Passion--all crosses, statues, and paintings in the churches being draped in purple, with a view to concentrating the attention of the worshippers on the sufferings of the Redeemer. ”
