I am not too sure about whether the moral lesson is mercy or not. Portia only manages to resolve the case not by mercy but by following the law to the precise letter, and Shylock is not actually shown much mercy. I think in many ways, having lost his daughter and his wealth, he would have preferred death to losing his religion as well. Portia speaks very prettily about mercy, and yet the rest of the play seems to question the limits of mercy.

It seems to me that the moral of the story can be summed up with Portia's famous speech to the court and to Shylock:

The quality of mercy is not strained.
It droppeth as the gentle rain from heaven
Upon the place beneath. It is twice blest:
It blesseth him that gives and him that takes.
'Tis mightiest in the mightiest; it becomes
The throned monarch better than his crown.
His scepter shows the force of temporal power,
The attribute to awe and majesty,
Wherein doth sit the dread and fear of kings.
But mercy is above this sceptered sway;
It is enthroned in the hearts of kings;
It is an attribute of God himself;
And earthly power doth then show like God's
When mercy seasons justice.   (4.1)

This is what Portia was trying to get across to Shylock as he waited for his pound of flesh from Antonio.  I believe, though, that it was a lesson that all SHOULD have learned, although I realize that not all did learn it (Gratiano comes to mind as someone who really needed to learn about mercy).

What are moral questions in The Merchant of Venice?

One of the most pressing moral questions in the play concerns religious double standards. Shylock, as a Jew, is subjected to contempt, hatred, and oppression on a daily basis. As well as his Jewishness, people hate him for being a moneylender. This is a prime example of hypocrisy by the Christians of Venice, as moneylending was one of the few occupations open to Jews at that time.

Moneylending, or usury, was considered incompatible with Christian values, and so it was forbidden for Christians to lend money at interest. Nevertheless, Christian merchants and businessmen still beat a path to Shylock's door whenever they're short of money. Yet even once he's given them a loan, they'll still curse him to his face.

Shylock's bond may be cruel and inhuman, but as he points out himself, he's only asking for equality, albeit a kind of equality that we could well do without. Christians are allowed to avenge themselves on Jews, so why not the other way round? That Shylock is denied equality with Christians, and indeed is forced to convert to Christianity, is just one more example of the religious double standards to which he and his fellow Jews are subjected.

What are moral questions in The Merchant of Venice?

One moral issues in The Merchant of Venice is judging by appearances, a theme Bassanio encounters in Belmont, which also applies to both Antonio and Shylock. Bassanio seems to be the only one in the play who really understands the value of not judging by appearances. Not only does he win Portia by selecting the least well-appearing leaden casket (box), he earnestly values Antonio for the good that Antonio has done him, despite the appearances Antonio presents to Shylock, and he speaks respectfully to Shylock in the marketplace while trying to secure a loan despite Shylock's social appearances as a Jew.

Antonio gives the appearance of being upright, upstanding, generous, loving, kind, gentle and probably merciful. But when his behavior is examined in juxtaposition to Shylock, Antonio reveals himself to be unkind, unloving, prejudiced, hateful, cruel and mean-spirited. Shylock makes the mistake of judging by appearances. For example, he judged his contract to be sound in a court of law because by all appearances it was. He judged revenge to be his best course of action because revenge had served the Christians so well.

Other moral questions are justice versus mercy; religious hypocrisy; and truthfulness in a court of law, bearing in mind that Portia lied in court by her very presence.

What is the main message/theme in The Merchant of Venice?

The play is full of various themes, and different readers are going to find that different themes resonate more strongly than others. For me, one of the main messages that I always gravitate toward is the thematic emphasis on friendship. Antonio is a wonderful friend to Bassanio, and I always think that Antonio is simply far too nice and forgiving. Antonio knows that Bassanio is not a wise handler of money, yet Antonio decides to take a great personal risk for his friend. To Bassanio's credit, Bassanio tells Antonio to not go through with Shylock's deal. Bassanio is willing to give up (maybe temporarily) his scheme to gain a potential rich trophy wife in order to protect Antonio. I think this deep friendship between these two then can guide readers toward a different major theme in the play—the theme of love. There is brotherly love between Antonio and Bassanio, but the play also deals with romantic love between several of the characters. The love theme is one that I really enjoy talking about with students because I enjoy asking discussing whether Bassanio is ever truly in love with Portia.