Advice

Some advice from Jesus the son of Sirach, of the Old Testament:

Do no evil, and evil will never befall you.
Stay away from wrong, and it will turn away from you.
My son, do not sow the furrows of injustice,
and you will not reap a sevenfold crop.

Do not seek from the Lord the highest office,
nor the seat of honor from the king.
Do not assert your righteousness before the Lord,
nor display your wisdom before the king.
Do not seek to become a judge,
lest you be unable to remove iniquity,
lest you be partial to a powerful man,
and thus put a blot on your integrity.
Do not offend against the public,
and do not disgrace yourself among the people.

Do not commit a sin twice;
even for one you will not go unpunished.
Do not say, "He will consider the multitude of my gifts,
and when I make an offering to the Most High
God he will accept it."
Do not be fainthearted in your prayer,
nor neglect to give alms.

Do not ridicule a man who is bitter in soul,
for there is One who abases and exalts.
Do not devise a lie against your brother,
nor do the like to a friend.
Refuse to utter any lie,
for the habit of lying serves no good.
Do not prattle in the assembly of the elders,
nor repeat yourself in your prayer.

Do not hate toilsome labor,
or farm work, which were created by the Most High.
Do not count yourself among the crowd of sinners;
remember that wrath does not delay.
Humble yourself greatly,
for the punishment of the ungodly is fire and worms.

Do not exchange a friend for money,
or a real brother for the gold of Ophir.
Do not deprive yourself of a wise and good wife,
for her charm is worth more than gold.
Do not abuse a servant who performs his work faithfully,
or a hired laborer who devotes himself to you.
Let your soul love an intelligent servant;
do not withhold from him his freedom.
~ Ecclesiasticus 7: 1-21

And some quotes from Niccolo Machiavelli's "The Prince"
"A prince never lacks legitimate reasons to break his promise...A wise ruler ought never to keep faith when by doing so it would be against his interests...If an injury has to be done to a man it should be so severe that his vengeance need not be feared...It is better to be feared than loved, if you cannot be both...It is much more secure to be feared than to be loved...[A]ffairs should be managed in such a way that when they no longer believe, they can be made to believe by force...Politics have no relation to morals."

Concerning The Way In Which Princes Should Keep Faith (Chapter XVIII)

Therefore a wise lord cannot, nor ought he to, keep faith when such observance may be turned against him, and when the reasons that caused him to pledge it exist no longer. If men were entirely good this precept would not hold, but because they are bad, and will not keep faith with you, you too are not bound to observe it with them. Nor will there ever be wanting to a prince legitimate reasons to excuse this nonobservance....

But it is necessary to know well how to disguise this characteristic, and to be a great pretender and dissembler; and men are so simple, and so subject to present necessities, that he who seeks to deceive will always find someone who will allow himself to be deceived. One recent example I cannot pass over in silence. Alexander VI did nothing else but deceive men, nor ever thought of doing otherwise, and he always found victims; for there never was a man who had greater power in asserting, or who with greater oaths would affirm a thing, yet would observe it less; nevertheless his deceits always succeeded according to his wishes, because he well understood this side of mankind.

Therefore it is unnecessary for a prince to have all the good qualities I have enumerated, but it is very necessary to appear to have them. And I shall dare to say this also, that to have them and always to observe them is injurious, and that to appear to have them is useful; to appear merciful, faithful, humane, religious, upright, and to be so, but with a mind so framed that should you require not to be so, you may be able and know how to change to the opposite.

And you have to understand this, that a prince, especially a new one, cannot observe all those things for which men are esteemed, being often forced, in order to maintain the state, to act contrary to faith, friendship, humanity, and religion. Therefore it is necessary for him to have a mind ready to turn itself accordingly as the winds and variations of fortune force it, yet, as I have said above, not to diverge from the good if he can avoid doing so, but, if compelled, then to know how to set about it.

I think I'd rather follow the former person's advice than the latter's. It seems less ruinous to one's mind and soul, less exhausting to live with, and intuitively more sensible.