Genesis 1:26 And God said, Let us make man in our image, after our likeness
The Jews, in whose language Genesis was written, have never understood God to be a plurality of persons.
The Athanasian Creed states:
So the Father is God, the Son is God, and the Holy Spirit is God. And yet they are not three gods, but one God. So likewise the Father is Lord, the Son Lord, and the Holy Spirit Lord. And yet not three lords, but one Lord.
If there are not three but ‘one’ then it follows that they cannot speak to each other using the term ‘us’. If they use the term ‘us’ to speak amongst themselves then they cannot be ‘one God’ but must of necessity be three individuals.
The doctrine of the Trinity is a case of the ‘Emperor’s new clothes’ – reason must be set aside and the straightforward statements of God become meaningless.
Deuteronomy 6:4 Hear, O Israel: The LORD our God is one LORD:
Isaiah 44:8... Is there a God beside me? yea, there is no God; I know not any.
Isaiah 45:6 That they may know from the rising of the sun, and from the west, that there is none beside me. I am the LORD, and there is none else.
Mark 12:29... Jesus answered him, The first of all the commandments is, Hear, O Israel; The Lord our God is one Lord:
‘God’ in Genesis 1:26 is the Hebrew word ‘Elohim’
Elohim is translated in the King James Bible as God 2346 times; god(s) 244 times; judge(s) 5 times; GOD 1 time; goddess 2 times; great 2 times; mighty 2 times; angels 1 time; exceeding 1 time; God-ward + 04136 1 time; godly 1 time.
In common with a few other Hebrew words elohim can be either singular or plural. An example of elohim used to denote a single entity is in Exodus 7:1
Exodus 7:1 And the LORD said unto Moses, See, I have made thee a god (elohim) to Pharaoh: and Aaron thy brother shall be thy prophet.
Elohim does not denote a plurality of persons in one – it does not signify a ‘trinity’. That it denotes a single God in Genesis 1:26 is shown by the singular pronouns which follow:
Genesis 1:27 So God created man in his own image, in the image of God created he him; male and female created he them.
The angels were present at creation. Both God and the angels are called elohim.
Psalm 8:5 For thou hast made him a little lower than the angels (elohim),
Hebrews 2:7 Thou madest him a little lower than the angels;
God works through his angels. God in his dealings with men is always represented by an angel. God, angels and men share a common image and likeness. Reason and scripture dictate that God is speaking to his angels in Genesis 1:26, not to himself.
I hope you have found this helpful.