Question

what will shylock gain from his revengeful action

Answer 1

Antonio has called Shylock a dog, laughed at his losses, mocked at his gains, spoke ill about the Jewish Community. Antonio also does not take any interest from the people whom he lends money to whereas Shylock does take interest. So, obviously people will prefer lending money from Antonio than Shylock. Shylock is angry on Antonio as he disgraces his Community. Hence, Shylock will get a satisfaction by taking revenge on Antonio