Wilfred M. Mcclay said this quote

“ The study of history can be sobering and shocking, and morally troubling. One does not have to believe in original sin to do it successfully, but it probably helps. By relentlessly placing on display the pervasive crookedness of humanity's timber, history brings us back to earth, equips us to resist the powerful lure of radical expectations, and reminds us of the grimmer possibilities of human nature--possibilities that, for most people living in most times, have not been the least bit imaginary. With such realizations firmly in hand, we are far better equipped to move forward in the right way. ”