D&C 29

There was a common phrase made popular years ago by Flip Wilson - "the devil made me do it."    In modern revelation we learn some of the limits of his power or ability to tempt.  In this revelation we learn -

"...that little children are redeemed from the foundation of the world through mine Only Begotten;
47 Wherefore, they cannot sin, for power is not given unto Satan to tempt little children, until they begin to become accountable before me..."  (Doctrine and Covenants  Section 29:46 - 47)

That is Satan cannot tempt little children.  We know that little children become accountable around eight years of age -

"For all men must repent and be baptized, and not only men, but women, and children who have arrived at the years of accountability."  (Doctrine and Covenants Section 18:42)

And -

"...children shall be baptized for the remission of their sins when eight years old, and receive the laying on of the hands."  (Doctrine and Covenants Section 68:27)

We also know that Satan cannot know our thoughts for there is -

"...none else save God that knowest thy thoughts and the intents of thy heart."  (Doctrine and Covenants Section 6:16)