Are you going to make fun of Moses for stating "let us make man in "OUR" image?
Here is an example of two people being one: Gen 2:24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.
And another of what God means to be "one" with another: Jhn 17:21
That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.