Mosiah 3:19 For the natural man is an enemy to God, and has been from the fall of Adam, and will be, forever and ever, unless he yields to the enticings of the Holy Spirit, and putteth off the natural man and becometh a saint through the atonement of Christ the Lord, and becometh as a child, submissive, meek, humble, patient, full of love, willing to submit to all things which the Lord seeth fit to inflict upon him, even as a child doth submit to his father.
Moroni 7:11 For behold, a bitter fountain cannot bring forth good water; neither can a good fountain bring forth bitter water; wherefore, a man being a servant of the devil cannot follow Christ; and if he follow Christ he cannot be a servant of the devil.
1 Nephi 14:10 And he said unto me: Behold there are save two churches only; the one is the church of the Lamb of God, and the other is the church of the devil; wherefore, whoso belongeth not to the church of the Lamb of God belongeth to that great church, which is the mother of abominations; and she is the whore of all the earth.
The intent here is clear. There are those who belong to the true church of Jesus Christ, which is called the Church of Jesus of Latter-day Saints, and there are those who belong to the church of the devil. And those are the only two churches. We read elsewhere:
3 Nephi 27:8 And how be it my church save it be called in my name? For if a church be called in Moses’ name then it be Moses’ church; or if it be called in the name of a man then it be the church of a man; but if it be called in my name then it is my church, if it so be that they are built upon my gospel.
9 Verily I say unto you, that ye are built upon my gospel; therefore ye shall call whatsoever things ye do call, in my name; therefore if ye call upon the Father, for the church, if it be in my name the Father will hear you;
10 And if it so be that the church is built upon my gospel then will the Father show forth his own works in it.
But we read above that a man can be a servant of Christ, or a servant of the devil. And we must ask ourselves: Can we be a servant of Christ if we do not hearken to the light which is available to us? If we have the gospel available and will not hearken, how can we be his servant? To be his servant we must hearken to his voice, and his voice is spirit.
There may be those who do not belong to the true church, but who might be numbered among its tally in the above scriptures. When it comes to tallying such exceptions, the principle is explained clearly in scripture:
D&C 137:7 Thus came the voice of the Lord unto me, saying: All who have died without a knowledge of this gospel, who would have received it if they had been permitted to tarry, shall be heirs of the celestial kingdom of God;
8 Also all that shall die henceforth without a knowledge of it, who would have received it with all their hearts, shall be heirs of that kingdom;
Those who would have received the gospel with all their hearts will be counted properly in the final tally, but they are presently bound under the craftiness of men because they know not where the true church can be found. That is the principle.
D&C 125:12 For there are many yet on the earth among all sects, parties, and denominations, who are blinded by the subtle craftiness of men, whereby they lie in wait to deceive, and who are only kept from the truth because they know not where to find it—
There may be those whose names are counted among the church of the Lamb of God because they are nonmembers only by nature of a mere technicality, but when they come in contact with the truth, they will receive it with all their hearts.