The four kinds of effort: to restrain, to abandon to develop, and to preserve. A.ii.74.
Four qualities which show that their possessor has entered on the path to surety, and that he is definitely bent on the destruction of the āsavas: virtue, learning, ardent energy, wisdom. A.ii.76.
The Buddha describes how, when he gave himself up to meditation in order to win Enlightenment, Māra (Namuci) came to tempt him with his eightfold army of lust, discontent, hunger and thirst, craving, cowardice, doubt, hypocrisy and stupor. But the Buddha was firm, and Māra retired discomfited. SN.vs.425 49.
The four right efforts: for the non arising of evil, for the abandoning of evil, for the arising of profitable states, and for the increase and fulfilment of such states. A.ii.15; cp. D.ii.120; M.ii.11, etc.