Let us, using our ability to reason, start at the BEGINNING.
When we think about what is the nature and essence of existence itself, we begin to realise how incredible it is that ANYTHING WHATSOEVER, exists. There should only 'BE', nothing. Nothing at all, yet, here we are, where only nothing should 'BE'.
Before we came along, 'existence' already was. We had a beginning. We came out of what pre-existed us. So, what could possibly have pre-existed Existence Itself, that Existence Itself should come to be?
The question is a nonsense! To give it an answer, it would have to be: that for 'Existence Itself' to 'come to be', it would have to have had a beginning Itself, which means that 'Existence Itself' would have had to pre-exist Itself in order that it could 'come to be', which is a nonsense! Clearly, 'Existence Itself' did not begin. It is, Itself, the very 'substance' of what existence 'is', existing uncreated in its eternal nature and essence from eternity to eternity. (Psalm 89:2; Ecclesiasticus 39:24; 42:15-22)
This is NECESSARILY TRUE because:
If at some point there was NO EXISTENCE OF ANY KIND WHATSOEVER, that is, if there was at some point ABSOLUTE NON-EXISTENCE, still now, and forever, there would FOREVER 'BE'..... NOTHING, because from ABSOLUTE NOTHINGNESS no being or essence of any kind could ever issue or derive. There would NEVER be existence. There would NEVER be us. Yet, here WE, ARE !
So, it is clear that we, as created existences, have derived and issued from the 'substance' of what is the nature and essence of what is the eternally uncreated 'substance' and 'essence' of what is Eternal Existence Itself, which could forever say of Itself: "I AM, I AM WHO AM" (Exodus 3:14; John 8:58) which is the verbal expression of Its own timeless, eternal essence and existence. No beginning. No end. "I AM the first, and I AM the last, and besides Me there is no God." (Isaiah 44:6,24; Apocalypse 22:13)
This is 'He-Who-Is', Eternal Existence Itself, perceived, discerned, unveiled and exposed by reason. (Exodus 3:14) This is the hidden God unveiled, Who does not, and cannot, hide from reason rightly used. (Isaiah 45:15) The 'Eternal Wonder' which is, God Himself!
The prime and fundamental personal relationship of every creature is its own relationship with its Creator-Life-Source. With It (Him), we have life. Without It (Him), we are not. Who is joined to Him will draw life from Him forever, for God is Eternal Spirit and "Who is joined to God is One Spirit with Him." (Corinthians 6:17; John 4:24; 5:24)
Having thus perceived Him, the creature cannot help but gasp and cry out:
"O God, how great Thou art!
I see your Hand and Mind
in everything You have made
You made me; You love me!
We are all Your children.
Blessed be God forever"
(1 John 4:8,16; Acts 17:28)