"Every battle is won or lost before it is fought," says Sun Tzu in The Art of War. It is the preparation prior to the commencement of the action, as well as the condition of the military-industrial complex of the nation, that will determine the overall outcome of the war. This is why Horatio Nelson, as the Battle of Trafalgar was about to commence on October 21, 1805, did not send detailed instructions to his fleet, but the simple reminder: "England expects that every man will do his duty." He knew the tactical work had already taken place.
See also the Second World War. The United States suffered an apparent catastrophic blow to its Pacific fleet in the Japanese attack on Pearl Harbor. Yet not only would the US recover, it would defeat and devastate the Japanese fleet at the Battle of Midway six months later. H.P. Wilmott writes, "such was the scale of the American industrial power, that if during the Pearl Harbor attack the Imperial Navy had been able to sink every major unit of the entire US Navy and then complete its own construction programmes without losing a single unit, by mid-1944 it would still not have been able to put to sea a fleet equal to the one the Americans could have assembled in the intervening thirty months."
It is a similar lesson in combating sin. Victory is not achieved in the moment of temptation. By then the outcome of the battle has already been determined. It is in the preparation, namely in the time of peace outside the near occasion of sin, when we resolve through our prayer lives to always do the Lord's will. We may still sin, but the fall will not mean we have lost the war.