War is something we should be working might and main to avoid.
(with) might and main
With as much effort or strength as one can muster. She attacked that punching bag with might and main.If you're not happy in your current job, then you should be working might and main to find a new one.
with might and main
with all your force.
Main derives from the Old English word mægen meaning ‘physical strength’ (see also by main forceat main). The use of the two nouns might and main together dates from the mid 15th century; main in this sense is no longer used in modern English except in this phrase.