According to Catherine Thomas, charity is another spiritual gift given to mortals in increments called grace. The Greek word behind grace in the New Testament means "divine gift." It refers to divine gifts of power unlocked by the Atonement. Grace, like all divine gifts, is administered to mortals through the Holy Ghost. It helps them do what they could not do by themselves. [Catherine Thomas, "A More Excellent Way," in Studies in Scripture: Book of Mormon, Part 2, p. 278]
[Moroni 7:45-47] Charity Suffereth Long, and Is Kind, . . . :
In Moroni 7, Moroni quotes Mormon as saying the following:
And charity suffereth long, and is kind, and envieth not, and is not puffed up, seeketh not her own, is not easily provoked, thinketh no evil, and rejoiceth not in iniquity but rejoiceth in the truth, beareth all things, believeth all things, hopeth all things, endureth all things. Wherefore, my beloved brethren, if ye have not charity, ye are nothing, for charity never faileth. Wherefore, cleave unto charity, which is the greatest of all, for all things must fail-- But charity is the pure love of Christ, and it endureth forever; and whoso is found possess of it at the last day, it shall be well with him. (Moroni 7:45-47)
According to Hugh Nibley, it appears that here Mormon goes into a long section directly from the New Testament. Aha! Moroni is quoting Paul here in the Book of Mormon! Or is he? In 1 Corinthians 13:4-9 Paul says the following:
Charity suffereth long, and is kind; charity envieth not; charity vaunteth not itself, is not puffed up. Doth not behave itself unseemly, seeketh not her own, is not easily provoked, thinketh no evil; rejoiceth not in iniquity, but rejoiceth in the truth; Beareth all things, believeth all things, hopeth all things, endureth all things. Charity never faileth; but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away. For we know in part, and we prophesy in part. But when that which is perfect is come, then that which is in part shall be done away.
Paul gives an operational definition of charity here, as you may notice. Charity is an intimate, subjective thing--very hard to define. Unless you have it, you don't know what it is. It's like indigestion or gift for music or math or something like that. You have to have it. That's what charity is, very hard to define. It's impulsive, and yet it's ongoing. It can't be faked; it can't be artificial. . . .
Although Paul's definition of charity is quoted in the Book of Mormon, Paul was himself quoting another work. He was quoting an old hermetic work on the subject. Richard Reitzenstein and some others showed that [to be the case] some years ago, and it's typical of the hermetic writings. In fact yesterday I was reading an apocalyptic work I'd never read before, and it gives exactly the same analysis of charity. This was a very common theme, not only with the philosophers. We know, especially from recent research, that Paul quoted all over the place. He quoted about every classical writer you can name. Possibly half the statements of Paul are quotations from the classics, from the orators, from the plays, etc. Paul quoted all over the place; he was a very learned man. What Paul's quoting here [in Corinthians 13] is from an ancient writing, and it's quoted here [by Mormon] in the Book of Mormon. Where we find it is in the hermetic writings which were taken over from the Jews at a very early time. Remember, Moroni was going through the records now and picking out the best things. So he picked the best definition he could find on charity [which just happened to be the same definition as given by Paul, and the same definition as given by his father Mormon]. It's the best thing you can find on charity. [Hugh W. Nibley, Teachings of the Book of Mormon, Semester 4, pp. 283-284]