After Jesus blesses the parents, then he turns to the children and blesses each one of them. Concerning this action, John Welch has this to say:
I think it's significant that the text says, after [Jesus] concludes this blessing [of the children], that he turns to the parents and says, "Behold your little ones" (3 Nephi 17:23). It seems to me--and again I just suggest this for your pondering--that Jesus is doing something more here than simply saying: look at your little kids--aren't they cute? Aren't they cute little guys? He's saying "behold your little ones." In some sense now I think they are their little ones, in a sense that they weren't prior to the time this blessing was given. . . . You remember that the parents witness what has gone on. Angels descend and minister, and thus this portion of the Sermon at the Temple is witnessed by God, angels, and the parents as witnesses. The suggestion, of course, is that some form of priesthood blessing has been given which now brings these families together in a special, spiritual way. They would never be the same as families, in any event, having experienced this great event together as a family unit. [John W. Welch, "Sacrament Prayers, Implications of the Sermon at the Nephite Temple," in Teachings of the Book of Mormon, Semester 4, p. 146]
3 Nephi 17:24 Angels . . . came down and encircled those little ones about ([Illustration]): Christ in America [Robert T. Barrett, Verse Markers, Book of Mormon, Vol. 1, p. 6]