Mark you this, Bassanio,
The devil can cite Scripture for his purpose.
An evil soul producing holy witness
Is like a villain with a smiling cheek,
A goodly apple rotten at the heart.
Oh, what a goodly outside falsehood hath! (A I, s iii)

While negotiating with Shylock for Bassanio’s loan, Antonio warns Bassanio that Shylock can be manipulative. Antonio describes Shylock as a “villain” who lies for his own purposes. While Antonio speaks from his personal opinion, readers become aware that many others feel this way about Shylock.

I am bid forth to supper, Jessica.
There are my keys.—But wherefore should I go?
I am not bid for love. They flatter me.
But yet I’ll go in hate to feed upon
The prodigal Christian. (A II, s v)

While speaking with Launcelot and his daughter Jessica, Shylock’s bossy demeanor reveals him to be a contradictory individual. As he discusses the dinner invitation he received from Bassanio and Antonio, he complains that the invitation is not motivated by friendship but by business. In the next breath, he reveals he’ll attend to spite them. He wants acceptance as an individual, but he reacts with equal hatefulness to the very hatred he decries.

The patch is kind enough, but a huge feeder,
Snail-slow in profit, and he sleeps by day
More than the wildcat. Drones hive not with me.
Therefore I part with him, and part with him
To one that would have him help to waste
His borrowed purse. Well, Jessica, go in.
Perhaps I will return immediately.
Do as I bid you. Shut doors after you.
Fast bind, fast find.
A proverb never stale in thrifty mind. (A II, s v)

While speaking to Jessica about Launcelot, Shylock ironically asks her to lock herself up, unaware that she secretly plans to escape his locked house. Shylock remains oblivious to how the people around him really feel. Shylock focuses on what he needs or wants, seeing others as either assets to use or obstacles to overcome. His self-absorption causes him to lose his daughter and financial wealth that night.

I never heard a passion so confused,
So strange, outrageous, and so variable,
As the dog Jew did utter in the streets.
“My daughter! O my ducats! O my daughter,
Fled with a Christian! O my Christian ducats!
Justice, the law, my ducats, and my daughter! (A II, s viii)

Solanio describes Shylock’s reaction to discovering his daughter Jessica’s deception. Solanio explains how Shylock appeared conflicted in his grief, seeming more concerned that he lost money to a Christian than that he lost his daughter. Shylock’s greed and misplaced priorities reveal his true character as a man who will do anything for wealth and his own status.

If it will feed nothing else, it will feed my revenge. He hath disgraced me and hindered me half a million, laughed at my losses, mocked at my gains, scorned my nation, thwarted my bargains, cooled my friends, heated mine enemies—and what’s his reason? I am a Jew. Hath not a Jew eyes? . . . If a Jew wrong a Christian, what is his humility? Revenge. If a Christian wrong a Jew, what should his sufferance be by Christian example? Why, revenge. The villainy you teach me I will execute—and it shall go hard but I will better the instruction. (A III, s i)

Shylock tells Salarino and Solanio about his promise to get revenge on Antonio and those who mistreated him over the years because he is Jewish. Shylock’s rant clarifies the fact that he will not take payment for Antonio’s death because he values revenge more. His anger and resentment continue to fuel his need for revenge.

Why, there, there, there, there! A diamond gone cost me two thousand ducats in Frankfurt—the curse never fell upon our nation till now! I never felt it till now—Two thousand ducats in that, and other precious, precious jewels. I would my daughter were dead at my foot and the jewels in her ear! Would she were hearsed at my foot and the ducats in her coffin! (A III, s i)

Here, Shylock rants about the money and jewels that his daughter Jessica took from him when she ran away. He is clearly more upset about the loss of possessions than about the loss of his daughter. Any concern about his daughter arises only as she represents a return of his possessions. Again, Shylock’s selfish, greedy, and dark character comes through as he wishes for the return of his daughter dead or alive so he could get his jewels back.

Out upon her! Thou torturest me, Tubal. It was my turquoise. I had it of Leah when I was a bachelor. I would not have given it for a wilderness of monkeys. (A III, s i)

Shylock responds to Tubal’s reports about Antonio’s ships and his daughter’s activity. Shylock, a vengeful character, feels joy upon hearing of Antonio’s misfortunes. At the same time, Shylock feels distraught about Jessica’s use of his money, clearly more concerned about not getting his money back than his daughter’s well-being. However, Shylock shows a glimpse of sentimentality in valuing the turquoise ring simply because it was a gift from his wife.

Never did I know
A creature that did bear the shape of man
So keen and greedy to confound a man.
He plies the duke at morning and at night,
And doth impeach the freedom of the state
If they deny him justice. Twenty merchants,
The duke himself, and the magnificoes
Of greatest port have all persuaded with him.
But none can drive him from the envious plea
Of forfeiture, of justice, and his bond. (A III, s ii)

Salarino describes how Shylock would rather take Antonio’s flesh than any amount of money to pay his debt because such a violent act would give him the revenge he has always wanted. Salarino explains how Shylock’s hatred fuels his strong need for revenge. While Shylock has valid reasons for his hatred, he has allowed his hate to take over his character and blind him.

You’ll ask me why I rather choose to have
A weight of carrion flesh than to receive
Three thousand ducats. I’ll not answer that
But say it is my humour. Is it answered?
What if my house be troubled with a rat
And I be pleased to give ten thousand ducats
To have it baned? What, are you answered yet?...
So can I give no reason, nor I will not
(More than a lodged hate and a certain loathing
I bear Antonio), that I follow thus
A losing suit against him. Are you answered? (A IV, s i)

Shylock answers the Duke’s question of why he prefers a pound of Antonio’s flesh over the money being offered. He explains that he has no reason other than his hatred for Antonio and because he wants to pursue this case against him. Such an explanation highlights Shylock’s relentless and unforgiving character. He feels no obligation to give valid reasons for his decisions and has a complete lack of concern for morality.

O, be thou damned, inexecrable dog,
And for thy life let justice be accused!
Thou almost makest me waver in my faith
To hold opinion with Pythagoras
That souls of animals infuse themselves
Into the trunks of men. Thy currish spirit
Governed a wolf who, hanged for human slaughter,
Even from the gallows did his fell soul fleet,
And whilst thou layest in thy unhallowed dam
Infused itself in thee, for thy desires
Are wolvish, bloody, starved, and ravenous. (A IV, s i)

After Shylock explains that he refuses to have mercy on Antonio or take money instead of Antonio’s flesh, even when offered twice what Antonio owes, a disgusted Gratiano compares Shylock’s character to a wolf used to slaughter humans. Gratiano’s impassioned comparison reveals how Shylock’s character has become more wild with revenge and anger throughout the play.