In Shakespeare's The Merchant of Venice, Bassanio strongly encourages Antonio not to agree to Shylock's bond.
In Act One, scene three, Bassanio has gone to Shylock, a Jewish money lender, to take out a loan in order to woo Portia, and win her hand. Antonio has already given Bassanio money and has no qualms about lending him more, but his assets are tied up in four shipping vessels that have yet to arrive home to provide him with an increased cash flow. So Antonio goes with Bassanio to basically co-sign the loan. (Shylock does not care much about Bassanio, but wants revenge against Antonio.)
To help Bassanio, Antonio agrees to guarantee the loan from Shylock. These two men have had difficulty in the past: Shylock lends money for interest; Antonio lends money without interest—it's his way. (Secretly Shylock hates him because he is a Christian, and lending money without charging interest causes Shylock to lose money because interest rates drop.)
Shylock adds a clause into their agreement, where he will change no interest, but should Antonio fail to repay his debt in the time allotted, Shylock will take a pound of Antonio's flesh, from whatever part of his body he chooses.
Antonio is unconcerned by this stipulation, which Shylock insists is simply a joke. Antonio is sure his ships will return a least a month earlier than the bond is due.
Bassiano, however, does not want his friend to risk anything for his sake, especially with Shylock, who is a greedy, nasty man. And although Bassiano repeats his request of Antonio, stating he'd rather go without, Antonio still agrees for the sake of his friend.
We learn in this segment of the play that Bassiano values Antonio's well-being even more than getting the money he needs to win Portia's hand. His own success is not as important as his friend's welfare. We can assume Bassanio is a caring, loyal and selfless friend.