“To know is to be certain. Uncertainty merely means that you don’t know. Knowledge is power because it is certain, and certainty is strength. Perception is temporary. It is an attribute of the space-time belief, and is therefore subject to fear or love. Misperception produces fear, and true perception induces love. Neither produces certainty because all perception varies. That is why it is not knowledge. True perception is the basis for knowledge, but knowing is the affirmation of truth.” (ACIM, COA ed., T-3.V.2:1-9)
We will return to the difference between perception and knowledge many times in A Course in Miracles; here we see the difference, elucidated in this quotation for today. Our perceptions vary, and our perceptions may be true or false. If they are false, they will elicit fear, and we will walk backward on the pathway. We need to invite true perception, being as loving as possible for us at all times. Love heals in its true perception, paving the way for knowledge that does not need to be proved.
We need certainty in our lives, and our attraction to knowledge will ensure that we will have certainty about many things. When we have certainty, we are sure about our decisions. The insights that we gain have an authority that they have been lacking heretofore. The insights carry the stamp of divine Authority, and this Authority is of God Himself.
If we are certain about something, we need not constantly second-guess ourselves. We need to stand on what we know, and when the ring of truth sounds, we will know that our guidance is true.
We will know what to do.
MIRACLES EACH DAY 
I agree! Only the one who knows can be certain about something. When we are certain, we possess courage. But when one does not know, he experiences uncertainty that evokes fear deep within. He comes to a close encounter with the X factor.
Good read!