Longstreet saw at once that Lee had heard enough about a flank movement. "With some impatience," Lee rejected the proposal and, pointing toward Cemetery Ridge, said that he was going to attack the Federals there with the three divisions of the First Corps. "I felt then, "Longstreet related afterward, "that it was my duty to express my convictions; I said, 'General, I have been a soldier all my life. I have been with soldiers engaged in fights by couples, by squads, companies, regiments, divisions, and armies, and I should know, as well as anyone, what soldiers can do.General, I have been a soldier all my life. I have been with soldiers engaged in fights by couples, by squads, companies, regiments, divisions, and armies, and should know, as well as any one, what soldiers can do. It is my opinion that no fifteen thousand men ever arranged for battle can take that position.
As quoted in General James Longstreet: The Confederacy's Most Controversial Soldier: A Biography (1993), by Jeffry D. Wert, New York: Simon & Schuster, p. 283
Thanks
The Union had the high ground.