In 1 Nephi 19:20, Nephi declares: "For behold, I have workings in the spirit, which doth weary me even that all my joints are weak, for those who are at Jerusalem." One might ask, What did Nephi mean by the expression "all my joints are weak"?
Quite often those who have great "workings of the spirit" feel weakened, almost incapacitated by them. This is true of both agony for sins and the ecstasy of the Spirit. (Mosiah 27:19-29; Alma 18:40-43; 22:18) As recorded in the book of Psalms, speaking prophetically for the Messiah, David said, "I am poured out like water, and all my bones are out of joint: my heart is like wax; it is melted in the midst of my bowels." (Psalm 22:14) Though Nephi's language is figurative, it describes an experience that is very real to those who have felt it. Jeremiah, whom Nephi could have known, said he had to preach the gospel because "his word was in mine heart as a burning fire shut up in my bones, and I was weary with forbearing, and I could not stay." (Jeremiah 20:9) It is not unusual to hear those who have premonitions say, "I can feel it in my bones." In the depths of his soul, Nephi knew that the Jews in Jerusalem had suffered the fate his father said they would. [Church Educational System, Book of Mormon Student Manual, Religion 121-122, 1981, p. 53]