… is from page 122 of the 1969 Arlington House edition of Ludwig von Mises’s 1944 Yale University Press book, Omnipotent Government: The Rise of the Total State and Total War (available free-of-charge on-line here):
Social coöperation and division of labor are man’s foremost tools in his struggle for survival. The intensification of this mutuality in the direction of a world-embracing system of exchange has considerably improved the conditions of mankind. The maintenance of this system requires lasting peace. The abolition of war is therefore an important item in man’s struggle for survival.