Today is Shakespeare's birthday. It is also the anniversary of the day on which he died. Compassion, as you know, is the foundational principle of meditative practice. This is actually what Shakespeare meant by the word, "mercy". Take a look at this passage from Measure for Measure:
No ceremony that to great ones 'longs,
Not the king's crown, nor the deputed sword,
The marshal's truncheon, nor the judge's robe,
Become them with one half so good a grace
As mercy does.