Act 3, Sc. 2, Lines 1-25: Why is it fitting that Hamlet gives the actors advice about how to act?

Enter Hamlet and the Players.

Hamlet. Speak the speech, I pray you, as I pronounced it to

you, trippingly on the tongue; but if you mouth it as many of

your players do, I had as lief the town-crier spoke my lines.

Nor do not saw the air too much with your hand, thus, but

use all gently; for in the very torrent, tempest, and, as I may

say, whirlwind of your passion, you must acquire and beget

a temperance that may give it smoothness. O, it offends me

to the soul to hear a robustious periwig-pated fellow tear a

passion to tatters, to very rags, to split the ears of the

groundlings, who for the most part are capable of nothing

but inexplicable dumb-shows and noise. I would have such

a fellow whipped for o'erdoing Termagent. It out-Herods

Herod. Pray you avoid it.

1st Player. I warrant your honour.

Hamlet. Be not too tame neither, but let your own discretion

be your tutor. Suit the action to the word, the word to the

action, with this special observance, that you o'erstep not the

modesty of nature. For anything so o'erdone is from the

purpose of playing, whose end, both at the first and now,

was and is to hold as 'twere the mirror up to nature; to show

virtue her feature, scorn her own image, and the very age

and body of the time his form and pressure. Now this

overdone, or come tardy off, though it makes the unskillful

laugh, cannot but make the judicious grieve, the censure of

the which one must in your allowance o'erweigh a whole

theatre of others.