But he who hates his brother is in the darkness, and walks in the darkness, and doesn't know where he is going, because the darkness has blinded his eyes.
Notice the progressive power of three successive antitheses in  1 John 2:9-11.  The antithesis of  1 John 2:9 is  1 John 2:10, and the antithesis of  1 John 2:10 is  1 John 2:11, the argument growing stronger with each new antithesis.  The conclusions are arranged in an ascending order of power.  1 John 2:9 has "is in darkness";  1 John 2:10 has "abiding in light, and there is no occasion of stumbling"; and  1 John 2:11 has a triple predicate: (1) "is in darkness"; (2) "walketh in darkness"; and (3) "knoweth not whither he goeth."