I have manifested thy name unto the men which thou gavest me out of the world: thine they were, and thou gavest them me; and they have kept thy word.
Note 96 at Joh 17:6: These disciples had not been sinless. They had sinned greatly (ex. Mt 16:22-23, Mr 9:33-34, and Lu 22:24), and they would all forsake Jesus and flee in just an hour or two (Mr 14:50). Therefore, we can see that Jesus doesn't consider keeping His word as walking in sinless perfection.