In this play, which was modeled on Shakespeare's Antony and Cleopatra, John Dryden makes a plea for moderation. Antony and Cleopatra lose everything because of their immoderate love and the play argues that this is not the best course of action. The significance of the title lies in that sacrificing "all" for love is a tragic mistake.
The play has been interpreted as advice to Dryden's patron, Thomas Osborne, the earl of Danby, to moderate his passion for his French-Catholic mistress, the Duchess of Portsmouth. Despite his love for a Catholic, Danby also backed severe curtailments of both Catholic and Dissenter rights in England. Dryden uses the play to argue in general for moderation.
Antony and Cleopatra's excessive love lead to distrust as well as disastrous military and political miscalculations. They both end up committing suicide: doing all for love is not a good idea.