Flogged by Deputy
When Henri IV. of France abjured Protestantism and was received into the Catholic Church, in 1595, two ambassadors were sent to Rome who knelt in the portico of St. Peter, and sang the Miserere. At each verse a blow with a switch was given on their shoulders.
Strange as this may seem, yet numerous examples occur in the Scriptures; thus, for David's sin thousands of his subjects were “flogged to death by deputy;” and what else is meant by the words “by his stripes we are healed”?
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894