A straw man argument. Simply because you wish to quote Satan as speaking in agreement with you does not mean Satan is telling a truth that you suggest..........Of course by presenting Satan's logic you would have us believe the Word of God contradicts itself. Wrong. Satan is a liar and the father of lies. You are of your father, the devil, and the lusts of your father you will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him, When he speaketh of his own; for he is a liar, and the father of it." -- John 8:44 
Satan was not giving the Christ a geography lesson.........Satan was pointing to all the known (at that time) kingdoms of the world trying to tempt the Christ with power. Satan's word clearly does not establish truth for the God of creation as you are attempting to erect your straw man, the word of God burns it to the ground. No where does the word of God represent the earth as being flat.
"When He prepared the heavens, I was there, when He drew a circle on the face of the deep." (Prov. 8:27). "It is He who sits above the circle of the earth, and its inhabitants........." -- Isaiah 40:22. Before you attempt another straw man argument by claiming that a circle can be flat and one dimensional...........the Hebrew word used for Circle is "chuwg" which means something that is dome shaped or round like a ball. This word is used in another example, "Clouds are a hiding place for Him, so He cannot see; and He walks on the vault (chuwg) of heaven." -- Job 22:14 Dome fits both descriptions for the earth and the heavens/atmosphere/sky.
Thus, simply because YOU QUOTE the devil.........does not make that quote truth. To find truth...........one MUST RIGHTLY DIVIDE THE WORD OF TRUTH. -- 2 Tim. 2:15