In act 4 scene 3 what does Malcolm tell Macduff to do with his grief?

Building on the last reply, this idea of "take it like a man" is repeated throughout the play.  Lady Macbeth first goads Macbeth into killing Duncan by suggesting that he is less than a man.  Lady Macduff, in her conversation with her son, also insults her husband's manliness.  Macduff, the "hero" at the end, is the only character to routinely exhibit elements of compassion.  Thematically, Shakespeare appears to be criticizing behavior that is overly "macho".  As he was writing this shortly after King James ascent to power in England, he might have been giving credit to the better leadership provided by a woman, in the form of Queen Elizabeth.