A bow long bent at last waxeth weak.

Sustained pressure can weaken something that initially seems strong. The bent bow makes the cost of prolonged strain tangible.

Applied to people, the proverb warns that endurance has limits. Allowing pressure to continue without relief may leave someone less able to meet later demands.

Use it as a warning against placing someone under unrelenting demands, or as a reason to allow rest before further effort is expected. It emphasizes the cumulative effect of strain rather than a single difficult task.