Act 1, Sc. 5, lines 148-170: Infer why Hamlet doesn't tell the others what the ghost has told him and why he swears them to silence.

Hamlet: Never make known what you have seen tonight.

Horatio/Marcellus: My lord, we will not.

Hamlet: Nay, but swear 't.

Horatio: In faith, my lord, not I.

Marcellus: Nor I, my lord, in faith.

Hamlet: Upon my sword.

Marcellus: We have sworn, my lord, already.

Hamlet: Indeed, upon my sword, indeed.

Ghost: [cries under the stage]. Swear.

Hamlet: Ha, ha, boy, sayst thou so? Art thou there, truepenny?

Come on, you hear this fellow in the cellerage.

Consent to swear.

Horatio: Propose the oath, my lord.

Ghost: [beneath]. Swear.

Hamlet: Hic et ubique? Then we'll shift our ground.

Come hither, gentlemen.

And lay your hands again upon my sword.

Swear by my sword

Never to speak of this that you heard.

Ghost: [beneath]. Swear by his sword.

Hamlet: Well said, old mole. Canst work i' th' earth so fast?

A worthy pioner! Once more remove, good friends.

Horatio: O day and night, but this is wondrous strange.