Evil is not-being and has no ground, for if it had a ground it would be necessary. Evil is a privation of good.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

““The Holy Trinity loves Itself in us and in Itself;† It sees and moves Itself.” Sin has its source in freedom: it arose because man turned towards himself instead of towards God. Evil does not have its ground in God, for in God there is no idea of evil. Evil is not-being and has no ground, for if it had a ground it would be necessary. Evil is a privation of good. The Logos is the principle that brings the many back to the One, and man back to God; it is thus the Saviour of the world. By union with God, the part of man that effects union becomes divine. John disagrees with the Aristotelians in refusing substantiality to particular things.” source