“The One God is, in the ontological sense, The True God.”

The One God is, by definition, one. He is whole, complete, and self-sufficient.

The True God is, by definition, true. He is the God who is actually God, the actual creator and sustainer of our life.

We preach One God, who is also the True God. There are not multiple deities running around in Heaven. If we preached only One God, some other religion could say, “Yes, your One God exists, but he's just a secondary God to N., who is truly god, because N. rules over all other gods.” Therefore we as Christians preach One God, who is also the true God. In other words, we aver that the God who is One is also God.

This dogma, then, is somewhat self evident. If there really is only one God, then that God has to really and truly be God. If that one God were not truly God, then there would be multiple gods, because some other god could then be really God. Two or more gods would be set up in this case, the “one” god who isn't really one because there is another, and the “true” god who really isn't truly god, because there is another.

By acknowledging our Oneness of our God, we also then acknowledge the rulership of our God. This is a source of commonality amongst Jewish, Muslim, and Christian peoples. We all recognize there is only one God, and that is the God whom we all strive to worship. By worshiping only the One God we are worshiping correctly in Spirit, but that does not imply correct worship in Truth (cf. John 4:24), so there are still differences in our religions.

Further reading: Cain's worship of the One God is rejected, because it is not in Truth even though it is in Spirit (Cain's heart was in it, but his actions didn't match up with the truth of what God wanted from him.) (Genesis 4:1-7).

"There is only One God."

There is a great mystery in God. We may get close to Him in war via patrons like St. Joan of Arc, or in peace via patrons like St. Francis of Assisi, yet He is one. We may talk of Him as Father, as Son, as Holy Spirit, yet He is one. We may read Scripture such as “Let us make man in our image” (Genesis 1:26), yet “Hear, O Israel! The Lord is our God, the Lord alone!”(Deuteronomy 6:4)

God is one. He is not a set of principles, or a union of pieces, He is whole. However, we as people are many and varied, so God in His infinite mercy, lets us come to Him as we are. When we talk about God in a variety of ways, partly what we are expressing is how we as people are varied and different – that each of us is unique, and that God values us for who we are.

Because we are unique, there is some variation in that narrow path (Matthew 7:13-14) which we must take to get to God. The path is narrow, because we must be holy, but it is not necessarily the same path for each person. Some, like the Blessed Chesterton or Saint Thomas, strove to become near God through feasting. Others, like Saint Francis or any number of the hermits strove to become near God through fasting. That variety, the feast and the fast, does not imply a duplicity of principles or a duplicity of gods, such that one is a god of plenty and one of poverty.

No, God is one, and there is no close challenger for His throne. He lets us come to Him in our plenty or our poverty, as long as we come to Him in love and with holiness. All the law and the prophets hang upon loving God (Mark 12:28-31) and keeping his commandments (John 14:15), yet in how we draw near to Him in love and obedience there is some variety.

When we speak in a variety of terms, then, it is a sign of Emmanuel, of God coming to be with us as we are. He loves you for who you are, He made you the way you are with a purpose, and He calls you to be who you are, but in holiness and love. God does not want to change you, but to purify you. He does not want to get rid of the variety among people, but to bring all people to love and holiness while still keeping their unique personality.

Further Reading: God is one (like a husband), not many like the Canaanite gods (Hosea 2).

"God is absolutely simple."

With humans, one may talk about various parts – the head, the hands, the feet. We are mosaic like beings with different pieces stuck together. Apart from the physical, we also are composed metaphysically – we have both hearts and minds, feelings and intellect.

God's ways, however, are not like ours. He is absolutely simple. Within Him there is no composition of lesser parts, no sum to form a whole – He is indivisible! In our physical world this can be hard to picture. Snow, seemingly homogeneous, is composed of flakes, which are composed of water and dust, the former composed of hydrogen and oxygen, both of which are further composed of electrons, neutrons, and protons, and all of those are yet even further composed of yet even smaller particles! All physical analogies fall short, because the lack of composition of God is partly related to the fact that God is Spirit (John 4:24). Certainly spirits can be composed of other spirits or whole, but I have yet to see something physical that isn't made up of parts.

What, then, is a proper analogy? Something like the Spirit of St. Louis would be a composite spirit, the spirit of adventure and exploration, the spirit of settlement and new lands. Rather, for a divided spirit, one would be better to think of love. Whole and pure, love drives out other competing spirits of lust and hatred. Love is not composed of other spirits, but solid and unified. It, like God, may be described with a variety of terms, but all the terms get at the same singular spirit of love.

God, then, is simple, because He is not complicated by numerous pieces. He is simple because He is not complex. He is a single mystery, rather than many pieced jigsaw puzzle. One cannot cut God into pieces and study Him any more than one can study life but cutting up dead animals. The whole might be illuminated by such a practice, but the true mystery remains unprobed.

Further reading: God's pedagogical laws teaching us how to be whole like God is whole, (Deuteronomy 22:9-11).
 
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