How important (as a christian) is it to perceive?

yourself as God sees (considers) you to be in order to do what you have been ordained to do? Had Abraham not seen himself as' the father of many nations' and the blessings were his (God giving him a continual reminder of what he was/was to become) would he have been considered 'the father of faith' ? And Moses ,had he not saw himself as 'a deliverer ' of the children of Israel (having being spoken to by God and convinced he was who God said he was) would he have died in the wilderness? These men became great (were ordained for greatness ) yet had they not saw themselves as God saw them and proclaimed them to be ,would they have succeeded in what they were called to do ? With this same mindset, for those of us that are christians ,how important is it for us perceive what God has said about us and that our consideration about ourselves to be the same as he said in his word ,for our examples succeeded only after they perceived (saw )themselves as He saw them ,so without this mindset ...will we be able to succeed in our daily lives or accomplish anything He has called for us to do?