Romans 10:15

“And how shall they preach, except they be sent, etc..] There is no proper, rightful, regular, and lawful preaching of the word without a mission, which is either extraordinary, or ordinary; extraordinary mission was such as the apostles themselves had; who, as they were called to extraordinary service, had extraordinary qualifications, and were sent forth in an extraordinary manner, with a power of doing miracles, and immediately by Christ himself. Ordinary mission is of men to be pastors and teachers, which includes qualifications for the ministerial work; for whom Christ sends forth into such service, he bestows gifts on them, fitting them for it, some more, some less, but all have some;…”

“as it is written-- (Isa 52:7). How beautiful are the feet of them that preach the gospel of peace, &c.--The whole chapter of Isaiah from which this is taken, and the three that follow, are so richly Messianic, that there can be no doubt "the glad tidings" there spoken of announce a more glorious release than of Judah from the Babylonish captivity, and the very feet of its preachers are called "beautiful" for the sake of their message.”

“And how shall they preach - In what way shall there be preachers, unless they are commissioned by God? The word “how” does not refer to the manner of preaching, but to the fact that there would be no preachers at all unless they were sent forth. To preach means to proclaim in a public manner, as a crier does. In the Scriptures it means to proclaim the gospel to people. Except they be sent - That is, except they are divinely commissioned, and sent forth by God. This was an admitted doctrine among the Jews, that a proclamation of a divine message must be made by one who was commissioned by God for that purpose; Jeremiah 23:21; Jeremiah 1:7; Jeremiah 14:14-15; Jeremiah 7:25. He who sends a…”

“But how shall they preach, unless they be sent - Thus by a chain of reasoning, from God's will that the gentiles also should "call upon him," St. Paul infers that the apostles were sent by God to preach to the gentiles also. The feet - Their very footsteps; their coming. Isa 52:7. Romans 10:16”

“And how: Jer 23:32; Mat 9:38, Mat 10:1-6, Mat 28:18-20; Luk 10:1; Joh 20:21; Act 9:15; Act 13:2-4, Act 22:21; Co1 12:28, Co1 12:29; Co2 5:18-20; Eph 3:8, Eph 4:11, Eph 4:12; Pe1 1:12 How beautiful: Isa 52:7; Nah 1:15 the gospel: Isa 57:19; Luk 2:14; Act 10:36; Eph 2:17, Eph 6:15 and bring: Isa 40:9, Isa 61:1; Luk 2:10, Luk 8:1; Act 13:26 Romans 10:16”