Whoso Repenteth and Cometh unto Me as a Little Child, Him Will I Receive

Christ continues to teach the descendants of Lehi (living in the Americas shortly after His death and Resurrection) about His purposes and redemptive power.

“Behold, I have come unto the world to bring redemption unto the world, to save the world from sin. Therefore, whoso repenteth and cometh unto me as a little child, him will I receive, for of such is the kingdom of God. Behold, for such I have laid down my life, and have taken it up again; therefore repent, and come unto me ye ends of the earth and be saved.” (3 Nephi 9:21-22)

Questions:

-What does it mean to come unto Christ as a little child?

-What prevents one from taking this all-import step in their lives?