Literally "train an army for a thousand days to use it for an hour"; emphasizes that extensive long-term preparation is necessary to be ready for a single moment of crisis.

literally 'train an army for a thousand days to use it for a single moment'; extensive preparation eventually pays off in a time of need

Literally "to train an army for a thousand days to use it for one morning"; long-term preparation is necessary for a single moment of crisis or opportunity.