1 Corinthians 16:9

“For a great door, etc.] Meaning an opportunity of ministering the word at Ephesus, a very populous city, and where he might have hope great good would be done. Some think that by this fair opportunity, or hopeful prospect, he means the populousness of the city; others, the conversion of some great men in it, which had made way for the introduction of Gospel there: but it seems rather to intend the desire that there appeared in many persons here to have the Gospel preached unto them; they flocked unto it; their hearts were opened to attend to it, and great numbers believed; and the apostle found a door of utterance in himself, and a door of entrance in them, which were reasons with him to…”

“door-- (Co2 2:12). An opening for the extension of the Gospel. Wise men are on the watch for, and avail themselves of, opportunities. So "door of hope," Hos 2:15. "Door of faith," Act 14:27. "An open door," Rev 3:8. "A door of utterance," Col 4:3. "Great," that is, extensive. "Effectual," that is, requiring great labors [ESTIUS]; or opportune for effecting great results [BEZA]. many adversaries--who would block up the way and prevent us from entering the open door. Not here false teachers, but open adversaries: both Jews and heathen. After Paul, by his now long-continued labors at Ephesus, had produced effects which threatened the interests of those whose gains were derived from idolatry,…”

“For a great door - There is abundant opportunity for usefulness. The word “door” is used evidently to denote an occasion or an opportunity for doing anything. It is the means by which we have entrance or access; and hence denotes facility in doing anything when there is no obstruction; see Acts 14:27; 2 Corinthians 2:12; Colossians 4:3. And effectual - That is, effective, or adapted to success; presenting opportunity for great effects. There is abundant opportunity to preach the gospel; there is attention to what is spoken, and great interest in it; there is great encouragement to labor. It is possible that this was one of the reasons why Paul had changed his mind about Macedonia. It would…”

“A great door - As to the number of hearers. And effectual - As to the effects wrought upon them. And there are many adversaries - As there must always be where Satan's kingdom shakes. This was another reason for his staying there. 1 Corinthians 16:10”

“a great: Act 19:8-10 door: Act 14:27; Co2 2:12; Col 4:3; Rev 3:7, Rev 3:8 there: Co1 15:32; Act 19:9, Act 19:10; Co2 1:8-10; Phi 3:18 1 Corinthians 16:10”