Not indeed that the Merchant is a small matter in himself; far from it: he is a highly interesting and attractive personage; nor am I sure but there may be timber enough in him for a good dramatic hero, apart from the Jew. Something of a peculiar charm attaches to him, from the state of mind in which we first see him. A dim, mysterious presage of evil weighs down his spirits, as though he felt afar off the coming-on of some great calamity. Yet this unwonted dejection, sweetened as it is with his habitual kindness and good-nature, has the effect of showing how dearly he is held by such whose friendship is the fairest earthly purchase of virtue. And it is considerable that upon tempers like his even the smiles of Fortune often have a strangely saddening effect. For such a man, even because he is good, is apt to be haunted with a sense of having more than he deserves; and this may not unnaturally inspire him with an indefinable dread of some reverse which shall square up the account of his present blessings. Thus his very happiness works, by subtle methods, to charge his heart with certain dark forebodings. So that such presentiments, whatever the disciples of positivism may say, are in the right line of nature:

"Oft startled and made wise By their low-breathed interpretings, The simply-meek foretaste the springs Of bitter contraries."

Shakespeare: His Life, Art, And Characters, Volume I. — Part 199

But the sorrow can hardly be ungrateful to us, that has such noble comforters as Antonio's. Our nature is honoured in the feelings that spring up on both sides.

Shakespeare: His Life, Art, And Characters, Volume I. — Part 199

Wealth indeed seldom dispenses such warnings save to its most virtuous possessors. And such is Antonio. A kind-hearted and sweet-mannered man; of a large and liberal spirit; affable, generous, and magnificent in his dispositions; patient of trial, indulgent to weakness, free where he loves, and frank where he hates; in prosperity modest, in adversity cheerful; craving wealth for the uses of virtue, and as the sinews of friendship;--his character is one which we never weary of contemplating. The only blemish we perceive in him is his treatment of Shylock: in this, though evidently much more the fault of the times than of the man, we cannot help siding against him; than which we need not ask a clearer instance of poetical justice. Yet even this we blame rather as a wrong done to himself than to Shylock; inasmuch as the latter, notwithstanding he has had such provocations, avowedly grounds his hate mainly on those very things which make the strongest title to a good man's love. For the Jew's revenge fastens not so much on the man's abuse of him as on his kindness to others.

Shakespeare: His Life, Art, And Characters, Volume I. — Part 199