Look thou be true; do not give dalliance

Prospero, to Ferdinand 
Look thou be true; do not give dalliance
Too much the rein. The strongest oaths are straw
To th’ fire i’ th’ blood. Be more abstemious,
Or else goodnight your vow.

The strongest oaths are straw
To th’ fire i’ th’ blood.

Ferdinand
I warrant you, sir,
The white cold virgin snow upon my heart
Abates the ardor of my liver.
Prospero
Well.—
Now come, my Ariel. Bring a corollary
Rather than want a spirit. Appear, and pertly.
 Soft music.