This is an excerpt from my dissertation that will be published sometime next year. I believe God is not only good but he is perfectly good.
This chapter will detail the premise that God’s essence is perfection using Old Testament passages. Leibniz proclaims, “God is an absolutely perfect being.” Moses professes, “The Rock, his work is perfect, for all his ways are justice. A God of faithfulness and without iniquity, just and upright is he” (Deuteronomy 32:4). Therefore there are certain properties which exist as part of an absolutely perfect being. One of those is goodness. The way mankind knows what is good is by reflecting on a standard. The standard for good is God. Therefore it is important to have an understanding of perfect goodness. Mark Murphy states,
What is this perfect goodness, a particular perfection exhibited by any absolutely perfect being? In recent work in philosophical theology — understandably, primarily in contexts in which the problem of evil is at issue — perfect goodness is understood as a practical excellence, an excellence concerned with desire, character traits, and action. A perfectly good being has the best desires that a being can have, and exhibits the best traits of character, and acts in an unsurpassably excellent way.
God is this perfect being. Also, two required attributes for a perfect being is omniscience and omnipotence.
Omniscience is required, so the position or opinions that produce perfect goodness do not change over time. A member of mankind is not a perfect being. They make decisions based on information the person possesses. Should the individual acquire additional information, it would require the individual to reaccess their position. By the perfect being possessing the attribute of omniscience he has all information and would never have to reaccess his position thereby making the perfect being immutable.
God’s knowledge or the depth thereof is inexhaustible, “Remember this and stand firm, recall it to mind, you transgressors, remember the former things of old; for I am God, and there is no other; I am God, and there is none like me” (Isaiah 46:8, 9). Murphy declares, “Thus we see that perfect goodness is often included in lists of the perfections exhibited by an absolutely perfect being: that being would not only be omniscient and omnipotent, but would also be perfectly good.”
 Leibniz, Leibniz: Discourse on Metaphysics Correspondence with Arnauld and Monadology, p. 3.
 Mark Murphy “Perfect Goodness”, The Stanford Encyclopedia of Philosophy (Spring 2014 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/ archives/spr2014/entries/perfect-goodness/>. Accessed May 15, 2017.