To those who were about to crucify him, the Christ said: “Woe unto you, scribes and Pharisees, hypocrites! because ye build the tombs of the prophets, and garnish the sepulchres of the righteous, and say, If we had been in the days of our fathers, we would not have been partakers with them in the blood of the prophets. Wherefore ye be witnesses unto yourselves that ye are the children of them which killed the prophets. Fill ye up then the measure of your fathers. Ye serpents, ye generation of vipers, how can ye escape the damnation of hell?” (Matthew 23:29-33.)
Surely it cannot be without significance that the citizenry of hell includes those who rejected the prophet or prophets of their own age in the pretense of loyalty to prophets then dead (see D&C 76:99-101). For a discussion on why people reject prophets and how the prophets’ claims should be evaluated, see Joseph Fielding McConkie and Robert L. Millet, Sustaining and Defending the Faith, chapter 5; see also Spencer W. Kimball, “Listen to the Prophets,” Ensign, May 1978, p. 77.
“He Clapped His Hands Upon All Them Who Were with Him”
Presumably this means that Alma laid his hands upon their heads and either set them apart to their assignments or else bestowed a special blessing upon them before they were to face a difficult challenge. In any case, thereafter “they were filled with the Holy Spirit.”