An effectual door shall be opened

1. 1 Cor. 16: 9
   9 For a great door and effectual is opened unto me, and there are many adversaries.
2. D&C 100: 3
   3 Behold, and lo, I have much people in this place, in the regions round about; and an effectual door shall be opened in the regions round about in this eastern land.
3. D&C 112: 19
   19 Wherefore, whithersoever they shall send you, go ye, and I will be with you; and in whatsoever place ye shall proclaim my name an effectual door shall be opened unto you, that they may receive my word.
4. D&C 118: 3
   3 Let the residue continue to preach from that hour, and if they will do this in all lowliness of heart, in meekness and humility, and long-suffering, I, the Lord, give unto them a promise that I will provide for their families; and an effectual door shall be opened for them, from henceforth.