Paul’s words “I am obligated” should properly be translated “I am a debtor.” There are two possible ways of getting into debt. The first is to borrow money from someone; the second is to be given money for someone by a third party. If a friend of yours had given me money to give to you, I would be in your debt until I handed it over. Your friend had put me in your debt.
It is in this second sense that Paul is in debt. He has not borrowed anything from the Romans which he must repay. Rather, Jesus Christ has entrusted him with the gospel for them. It is Jesus Christ who has made Paul a debtor by committing the gospel to his trust.
Paul was in debt to the Romans. As apostle to the Gentiles he was particularly in debt to the Gentile world. It was because of his sense of debt to them that he could write: “That is why I am so eager to preach the gospel also to you who are at Rome.”
Similarly, we are debtors to the world, even though we are not apostles. Because the gospel has come to us, we have no liberty to keep it to ourselves. Nobody may claim a monopoly of the gospel. Good news is for sharing. We are under obligation to make it known to others. It is universally regarded as a dishonorable thing to leave a debt unpaid. We should be as eager to discharge our debt as Paul was to discharge his.
From Reading Romans with John Stott by John Stott with Dale and Sandy Larsen.