...if Christianity has any distinctive meaning at all, it is that we can affirm or deny certain things about God, that we are not in a state of utter ignorance about His heart and nature, that we find in the character and work of Jesus Christ a reflection of the character and work and large purpose of God. We get at the fundamental qualities of His moral nature. We get no satisfaction about the metaphysics of the divine, but we do get satisfaction about the morality, the character, of the divine.
Let me premise also that when we speak about God's fundamental qualities we must be careful. All the qualities that go to make up His nature are, in a sense, fundamental qualities. They are all necessary. They are not there in such a way that they might as easily, or as well, be anywhere else. He does not live and move under our intellectual limitations. He is the foundation of all things, and His every aspect is an essential part of Him. There is in Him nothing transitory, careless, ornamental merely. "He is all centre, and no circumference."* Wherever He is, and He is everywhere, He is essential; nor can you say of Him that this quality or that is more of His essence than another. You cannot say His strength is a more fundamental quality of Him than His wisdom. His strength is wisdom. His wisdom is strength, both to Him and to us. Whatever He is, is eternal - is fundamental.
From P T Forsyth's sermon, Mercy the True and Only Justice, 1877, republished in Jason Goroncy's Descending on Humanity and Intervening in History, page 76
*Goroncy suggests that this is a reference to James Martineau's description of the universe in his book, Endeavours after the Christian Life.