Paul pushes the chain back one more step. There can be no preaching without sending. Barnes explains that Paul means preachers who are divinely commissioned, and that this "was an admitted doctrine among the Jews": a message from God had to be proclaimed by someone God sent. Gill says, "There is no proper, rightful, regular, and lawful preaching of the word without a mission," and he describes that sending as either extraordinary, as with the apostles, or ordinary, through the churches. The question points to the source of the whole chain: God, who sends.

Paul answers from Scripture: "as it is written, How beautiful are the feet of them that preach the gospel of peace, and bring glad tidings of good things!" (Romans 10:15). The quotation shows that God does send such messengers and that their coming is a welcome sight. Paul then admits that not all who heard believed (Romans 10:16) and draws the conclusion, "faith cometh by hearing, and hearing by the word of God" (Romans 10:17).

Paul is quoting Isaiah 52:7, where the feet of a messenger bringing good tidings appear "upon the mountains," and he says to Zion, "Thy God reigneth!" Barnes says Paul's wording is "taken from the Hebrew, with a slight variation," and that the feet stand for the messenger's coming: "How beautiful is the coming or the running of such a herald." In Greek, "preach" is kēryssō, to proclaim like a herald, and "sent" is apostellō, to send out. Gill notes that Jewish writers connected Isaiah 52:7 with the Messiah.

The good news does not start with the messenger. It starts with God, who sends. Isaiah's herald does not announce his own ideas; he announces that God reigns and brings salvation (Isaiah 52:7). Matthew Henry compares the preacher to an ambassador and asks, "How shall a man act as an ambassador, unless he have both his credentials and his instructions from the prince that sends him?"

That is why the feet are called beautiful. Barnes and Henry both tie the beauty to the welcome of the message. Henry explains the line this way: "How beautiful are the feet, that is, how welcome are they!" What makes a messenger lovely is the news God has given him to carry.