2 Nephi 9:20

"O how great the holiness of our God!  For he knoweth all things, and there is not anything save he knows it."
2 Nephi 9:20


The fact that God knows everything is, by itself, a reason to listen to God. :)  It's funny that we go throughout our lives thinking that we know so much, that God's rules don't apply to us in this or that way... when this is God we're talking about.  If anyone knows what he is doing, it is him.
The idea of knowing everything... wow.  I wonder sometimes if eventually we will all know everything, as we learn and grow throughout eternity.  And, if we all will eventually know everything, then that means we will know everything about each other... which is probably why it is hard to face living with God when we don't feel good about ourselves, or feel guilty about our actions.  Because he knows everything, and if we live there, then everyone around us will eventually know everything.  If we are ashamed of what we do and who we are, then how could we stand to face God, or to be in that place?  That is why God wants us to repent... so that we can become clean and pure again, and able to feel good about ourselves.  That kind of confidence in yourself and your relationship with God changes our lives... both earthly and eternal... dramatically.  Repentance is merely removing impediments to progress.  God's work is to help us to reach exaltation... and someone who knows everything is an excellent ally. :)