I believe you were probably thinking of his omniscience, being all powerful doesn't really take away the possibility of free will, where being all knowing might. James Talmage, in Jesus the Christ, I believe had a very good explanation of the omniscience of God:
Respecting the foreknowledge of God, let it not be said that divine omniscience is of itself a determining cause whereby events are inevitably brought to pass. A mortal father, who knows the weaknesses and frailties of his son, may by reason of that knowledge sorrowfully predict the calamities and sufferings awaiting his wayward boy. He may foresee in that son's future a forfeiture of blessings that could have been won, loss of position, self-respect, reputation and honor; even the dark shadows of a felon's cell and the night of a drunkard's grave may appear in the saddening visions of that fond father's soul; yet, convinced by experience of the impossibility of bringing about that son's reform, he foresees the dread developments of the future, and he finds but sorrow and anguish in his knowledge. Can it be said that the father's foreknowledge is a cause of the son's sinful life?
I once heard an explanation that makes sense. It's like seeing millions of paths, as time goes by some paths fade away and new ones unfold.