In earlier generations simplicity was regarded as an indispensable aspect of an orthodox doctrine of God. Anglicans, Presbyterians, Congregationalists, and Baptists all confessed that God is “without parts” and the Belgic Confession even made divine simplicity its opening affirmation: “We all believe with the heart, and confess with the mouth, that there is one only simple and spiritual Being, which we call God.” Nowadays, we hear very little about God’s simplicity. Many seminaries either don’t teach it or mention it only in order to disparage it as a needlessly abstruse and nonsensical doctrine. Even more rarely is it mentioned in church or explained to the congregants. This makes it difficult to believe and confess, to say the least. The unspoken assumption tends to be that nothing is lost by leaving aside this ancient doctrine. But is divine simplicity really so insignificant? Does it really matter?
—James Dolezal, “Why Divine Simplicity Matters”