God didn’t tell Abraham that he would conquer Canaan, so Abraham couldn’t have gone to Canaan and tried to destroy the promised land, because that was not God’s plan. Abraham couldn’t have “spoken it into existence” or “manifested victory” for something that God did not give him. Abraham was promised an heir and would only sojourn in the land of Canaan. God said that Abraham’s “seed” (descendants) would inherit the land of Canaan. In Genesis 15:13-16, God said Abraham would die before that would happen and that the promised land would be inherited over 400 years later, after enduring persecution and enslavement. No amount of “manifesting” would have changed God’s word. We can repeat God’s word in faith because he initiated the idea and does the work, but we cannot tell God what to do. Faith begins where the will of God is known.