Little children are redeemed from the foundation of the world through the atonement, "Wherefore, they cannot sin," the Lord has said, "for power is not given unto Satan to tempt little children, until they begin to become accountable before me; for it is given unto them even as I will, according to mine own pleasure, that great things may be required at the hand of their fathers.
— from Salvation Universal by Joseph Fielding Smith

Wherefore, they cannot sin, for power is not given unto Satan to tempt little children, until they begin to become accountable before me; 48.
— from History of the Church of Jesus Christ of Latter-Day Saints, Volume 1 Period 1. History of Joseph Smith, the Prophet by Smith, Joseph, Jr.