What does Proverbs 21:5 mean?

This verse contrasts carefully prepared work with last-minute decisions and sloppy choices. Those who think before they act, and who think well, tend to see better results than those who act on impulse or at the last moment. As a proverb, this is meant as a general statement, not an absolute guarantee. Attentive people can suffer loss, and careless people can stumble into success. Common sense, however, supports the idea that being lazy or negligent in planning typically leads to disaster (Proverbs 10:4; 12:23; 18:9).

Jesus references the difference between careful thought and senseless impulse when speaking of what it meant to become His follower. He asked: "For which of you, desiring to build a tower, does not first sit down and count the cost, whether he has enough to complete it?" (Luke 14:28). Starting to build without planning might lead to ridicule if the builder only had enough funds for the foundation (Luke 14:29–30). Jesus also referred to a king who considers whether his soldiers can defeat a force twice their size. Usually, a wise ruler would negotiate for peace (Luke 14:31–32).

Even when it comes to responding to Jesus' call to discipleship, a purely emotional reaction is unlikely to lead to anything but failure. Diligent thought about the cost of discipleship, leading a person to respond positively to Jesus' call, is far more likely to lead to loyalty and growth.