SOURCE FOR POLONIUS' ADVICE TO LAERTES?

From Volume 1 of the 1001 Nights, Englished by Sir Richard Burton:

Then Nur al-Din lapsed into a swoon, the forerunner of death; but presently recovering himself he said, “O Hasan, O my son, I will now bequeath to thee five last behests. The FIRST BEHEST is, Be over-intimate with none, nor frequent any, nor be familiar with any; so shalt thou be safe from his mischief; for security lieth in seclusion of thought and a certain retirement from the society of thy fellows; and I have heard it said by a poet:--

In this world there is none thou mayst count upon 

To befriend thy case in the nick of need:
So live for thyself nursing hope of none 

Such counsel I give thee: enow, take heed!

The SECOND BEHEST is, O my son:  Deal harshly with none lest fortune with thee deal hardly; for the fortune of this world is one day with thee and another day against thee and all worldly goods are but a loan to be repaid.  And I have heard a poet say:--

Take thought nor hast to win the thing thou wilt; 

Have ruth on man for ruth thou may’st require:
No hand is there but Allah’s hand is higher; 

No tyrant but shall rue worse tyrant’s ire!

The THIRD BEHEST is, Learn to be silent in society and let thine own faults distract thine attention from the faults of other men: for it is said:--In silence dwelleth safety, and thereon I have heard the lines that tell us:--

Reserve’s a jewel, Silence safety is; 

Whenas thou speakest many a word withhold;
For an of Silence thou repent thee once, 

Of speech thou shalt repent times manifold.

The FOURTH BEHEST, O my son, is Beware of wine-bibbing, for wine is the head of all frowardness and a fine solvent of human wits.  So shun, and again I say, shun mixing strong liquor; for I have heard a poet say:--

From wine I turn and whoso wine-cups swill;

Becoming one of those who deem it ill:
Wine driveth man to miss salvation-way, 

And opes the gateway wide to sins that kill.

The FIFTH BEHEST, O my son, is Keep thy wealth and it will keep thee; guard thy money and it will guard thee; and waste not thy substance lest haply thou come to want and must fare a-begging from the meanest of mankind.  Save thy dirhams and deem them the sovereignest salve for the wounds of the world.  And here again I have heard that one of the poets said:--

When fails my wealth no friend will deign befriend: 

When wealth abounds all friends their friendship tender:
How many friends lent aid my wealth to spend; 

But friends to lack of wealth no friendship render.

On this wise Nur al-Din ceased not to counsel his son Hasan till his hour came and, sighing one sobbing sigh, his life went forth. 

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Polonius' advice to Laertes, upon the youth's departure for France (Act 1, Scene 3):

Lord Polonius

Yet here, Laertes! aboard, aboard, for shame!

The wind sits in the shoulder of your sail,

And you are stay'd for. There; my blessing with thee!

And these few precepts in thy memory

See thou character. Give thy thoughts no tongue,

Nor any unproportioned thought his act.

Be thou familiar, but by no means vulgar.

Those friends thou hast, and their adoption tried,

Grapple them to thy soul with hoops of steel;

But do not dull thy palm with entertainment

Of each new-hatch'd, unfledged comrade. Beware

Of entrance to a quarrel, but being in,

Bear't that the opposed may beware of thee.

Give every man thy ear, but few thy voice;

Take each man's censure, but reserve thy judgment.

Costly thy habit as thy purse can buy,

But not express'd in fancy; rich, not gaudy;

For the apparel oft proclaims the man,

And they in France of the best rank and station

Are of a most select and generous chief in that.

Neither a borrower nor a lender be;

For loan oft loses both itself and friend,

And borrowing dulls the edge of husbandry.

This above all: to thine ownself be true,

And it must follow, as the night the day,

Thou canst not then be false to any man.

Farewell: my blessing season this in thee!

Laertes

Most humbly do I take my leave, my lord.