Luke 14:28-32

For which one of you, when he wants to build a watchtower [for his guards], does not first sit down and calculate the cost, to see if he has enough to finish it? Otherwise, when he has laid a foundation and is unable to finish [the building], all who see it will begin to ridicule him, saying, ‘This man began to build and was not able to finish!’ Or what king, when he sets out to meet another king in battle, will not first sit down and consider whether he is strong enough with ten thousand men to encounter the one who is coming against him with twenty thousand? Or else [if he feels he is not powerful enough], while the other [king]is still a far distance away, he sends an envoy and asks for terms of peace.