Full Idea
God and God alone must be held responsible for the good things, but responsibility for bad things must be looked for elsewhere, and not attributed to God.
Gist of Idea
God is responsible for the good things, but we must look elsewhere for the cause of the bad things
Source
Plato (The Republic [c.371 BCE], 379c)
Book Reference
Plato: 'Republic', ed/tr. Waterfield,Robin [OUP 1993], p.74