The unknown author of The Cloud of Unknowing writes:  “This foul, wretched lump called sin is none other than yourself and though you do not consider it in detail, you understand now that it is part and parcel of your very being and something that separates you from God.  And so reject the thought and experience of all created things but most especially learn to forget yourself…“.  

It is to work on racial prejudice for the benefit of your own spiritual growth and not so much for others!
The racial prejudice is mostly from self boasting and hating others you consider less worthy than you. 
 “Anyone who wishes to follow me let him forsake himself (ego self).”  (Matthew 16:24)
Your EGO self replaces God's presence!  Therefore EGO is enemy # 1 for Christ followers!