Being good per se, and by His own essence, God must needs be the chief Goodness in whom there is nothing but good.  From the chief goodness there can proceed nothing but good.  All good in existence must be oriented back to that chief goodness, and it itself must be the final cause of all good.

Nothing can add to Him or make Him better than He is.  Nothing can detract from Him and make Him worse.  Nothing can be added to Him, nothing can be severed from Him, no created good can render Him more excellent, and no evil from any creature can render Him less excellent.   “You are my Lord; I have no good apart from You” says the Psalmist (Psalm 16:2).