Some of us who seem quite nice people may, in fact, have made so little use of a good heredity and a good upbringing that we are really worse than those whom we regard as fiends. Can we be quite certain how we should have behaved if we had been saddled with the psychological outfit, and then with the bad upbringing, and then with the power, say, of Himmler? That is why Christians are told not to judge. We see only the results which a man’s choices make out of his raw material. But God does not judge him on the raw material at all, but on what he has done with it. Most of the man’s psychological makeup is probably due to his body: when his body dies all that will fall off him, and the real central man, the thing that chose, that made the best or the worst out of this material, will stand naked. All sorts of nice things which we thought our own, but which were really due to a good digestion, will fall off some of us; all sorts of nasty things which were due to complexes or bad health will fall off others. We shall then, for the first time, see every one as he really was. There will be surprises.
C.S. Lewis, Mere Christianity, p. 86-87