Hasty resolutions seldom speed well.

Decisions made hastily seldom turn out well. Here, "speed well" means to succeed or fare well, so the warning concerns the outcome of a rushed decision rather than the time it takes.

The saying urges careful consideration before settling on a course of action. It warns against deciding without enough thought, rather than against carrying out a considered decision promptly.

Use it when someone is about to settle an important matter without weighing the consequences, such as accepting an offer or making a commitment under pressure.