How does Shylock defend his practice of charging interest on loans, in Shakespeare's play, The Merchant of Venice?
In Shakespeare's The Merchant of Venice, Shylock tries to defend the charging of interest by referring to a Biblical story in the Old Testament.
The story he refers to is Jacob taking care of his uncle Laban's sheep (in the book of Genesis). Shylock relays the story of how Jacob manipulated an agreement with Laban to make out financially with regard to Laban's sheep.
Shylock describes Laban and Jacob agreeing that of Laban's sheep, any that were spotted would belong to Jacob. Shylock tries to say that Jacob had a way to provide for the birth of more spotted sheep than plain sheep.
Using a bit of superstitious "nonsense," Shylock explains what he says took place.
The skillful shepherd peeled me certain wands.
And in the doing of the deed of kind
He stuck them up before the fulsome ewes,
Who then conceiving did in eaning time
Fall parti-colored lambs—and those were Jacob’s.
In other words, the newborn sheep will look like whatever its mother saw while mating, so Jacob, knowing this, placed wands (a branch or stem of a tree) with spots on it, on the ground in front of the ewes. When the sheep were born, the many that were spotted, went to Jacob, according to Shylock, because of the steps Jacob had guaranteed to be successful. His thought is that trickery is not treacherous, as long as there is no outright stealing involved.
Antonio argues that the sheep were spotted because it was the will of God, not because of anything Jacob had done. And he asks Shylock what his point is, to prove that charging interest is a good thing?
This was a venture, sir, that Jacob served for—
A thing not in his power to bring to pass
But swayed and fashioned by the hand of heaven.
Was this inserted to make interest good?
Shylock will not be convinced otherwise, saying that this is what he practices when lending money:
I make it breed as fast.
So Shylock tries to twist the meaning of a Bible story to rationalize his uncharitable behavior.