which will not show without knocking.

(Troilus and Cressida, Act III, Sc. 3.)

Demetrius: “But be your heart to them

As unrelenting flint to drops of rain.

(Titus Andronicus, Act II, Sc. 3.)

Marcus: “My heart is not compact of flint nor steel.

(Titus Andronicus, Act V, Sc. 3.)

Gower: “Make raging battery upon shores of flint.

(Pericles, Act IV, Sc. 4.)

Poet: “The fire i’ the flint shows not till it be struck.