2 Co. 2:12-17- Furthermore, when I come to Troas to preach Christ’s gospel, and a door ( opportunity) was opened to my by the Lord, I had no rest in my spirit, because I did not find Titus my brother; but taking my leave of them, I departed for Macedonia. Now thanks be to God who always leads us in triumph in Christ, and through us manifests the fragrance of His knowledge in every place. For we are to God the fragrance of Christ among those who are being saved and among those who are perishing. To the one we are the aroma of death leading to death, and to the other the aroma of life leading to life. And who is sufficient for these things? For we are not, as so many (the rest), peddling the word of God, but as of sincerity, but as from God, we speak in the sight of God in Christ.
When the Lord opens a door for His word, there are always adversaries. ( I. Co. 16:9)
When the Lord opens a door for His word, it is for utterance to make known the mystery of the gospel, as ambassadors…(Eph. 6:19,20)
When the Lord opens a door for His word, There is a need for intercessors to pray, that the Lord would make known His word and manifest to those who receive it. (Col. 4:2,3)
Rev. 3: 7,8- These things says He who is holy, He who is true, “He who has the key of David, He who opens and no one shuts, an shuts and no one opens”: “I know your works. See, I have set before you an open door, and no one can shut it: for you have a little strength, have kept my word, and have not denied my name.”