How can God possess all these kinds of characteristics, and yet be described as simple?

The answer

Although we are aware of all these characteristics that inflame our souls with His sublime love, we cannot say that His essence is composed of many elements, or that there are elements external to Him that are incorporated into His simple essence.

St. John Chrysostom observes that the Seraphim and the Cherubim upon whom He is enthroned cannot comprehend His essence; they can only come to know Him through His glory and His divine works, as far as they can.

Fr. Tadros Yacoub Malaty