Napoleon's Tactic to Defeat the Russians

Napoleon's idea was every single person on the field of battle of the defeated if you don't get rid of him, he's going to come back and haunt you. And so he was he would unleash his Calvary and try to destroy them as a unit. There were pretty fierce people and it's. What do you think happened with that invasion of Russia? I mean, why did he why did he plan it to in the first place if it was sort of out of reach.