Perseverance, dear my lord,
Keeps honour bright: to have done is to hang
Quite out of fashion, like a rusty mail
In monumental mockery. [ Shakespeare ]

A rusty nail, placed near the faithful compass,
Will sway it from the truth, and wreck the argosy. [ Scott ]

That gloomy outside, like a rusty chest, contains the shining treasures of a soul resolved and brave. [ Dryden ]

When a man but half forgives his enemy, it is like leaving a bag of rusty nails to interpose between them. [ Latimer ]