Some have voiced concern over the manner in which Nephi killed Laban in the Book of Mormon. Laban was drunken and unconscious. The concern seems to be that the idea of killing someone who is unconscious, even if that man would be a threat when awake, somehow seems like something God would not approve of.
However, Goliath was unconscious, the same as Laban, when David smote off his head. In that unconscious state, Goliath was a threat to no one. He was laying on the ground, defenseless. Clearly, however, God assisted David in slaying Goliath. God delivered Goliath into David's hands, just as God delivered Laban into Nephi's hands. Nephi's actions are entirely consistent with David's actions and the will of God.