Sure I am of this, that you have only to endure to conquer.

The line compresses a familiar Churchillian wartime ethic: victory is less a matter of brilliance than of stamina under pressure. “Endure” implies holding fast through fear, deprivation, and uncertainty; “conquer” suggests that persistence itself becomes a form of agency, turning survival into eventual triumph. The phrasing (“Sure I am of this”) gives the claim a moral certainty, as if endurance is a law of history rather than mere encouragement. Read broadly, it frames adversity as a test of character and collective will, implying that the decisive battlefield is psychological—maintaining resolve long enough for circumstances, allies, or opportunities to shift in one’s favor.