As they wandered in the wilderness - delayed in reaching their expected goal of the land of milk and honey - the children of Israel murmured and criticized their leader Moses. This murmuring was a sign of spiritual weakness.
While the children of Israel directed their murmuring toward Moses and, perhaps, Aaron, his brother, they were actually criticizing the Lord. Moses said:" . . . The Lord heareth your murmurings which ye murmur against him: and what are we? your murmurings are not against us, but against the Lord." (Ex. 16:8.)
In one of his books, Notwithstanding My Weakness, Elder Neal A. Maxwell of the Council of the Twelve, wrote: "A scriptural survey of murmuring indicates it is equated with complaining. (See 1 Ne. 17:22.) It has occurred in an individual's heart or in groups out in the open or in the privacy of ancient Israel's tents. Common causes are: resentment at personal chastisement, as with Oliver Cowdery (D&C 9:6); pique at things withheld by the Lord, as with Emma Smith (D&C 25:4); lack of perspective or because of incomplete information (1 Ne. 2:12; 1 Ne. 16:3; Alma 58); reactions to persecution and fears (Mosiah 27:1; Num. 14:2; Deut. 1:27); failure to accept central doctrines and hard sayings (John 6:41, 61; 1 Ne. 16:1-2); and inability to sustain prophetic leaders, such as Moses and Nephi, which is really rebellion against the Lord. (Ex. 16:8-9; 2 Ne. 5:3.)" In another book, A Wonderful Flood of Light, Elder Maxwell pointed out, "As if damage to self were not enough reason to resist murmuring, another obvious danger is its contagiousness. . . . No one knows how to work a crowd better than the adversary."