Isaiah 1:18 “Come now, let us reason together, says the Lord: though your sins are like scarlet, they shall be as white as snow; though they are red like crimson, they shall become like wool.”
Discourse should be defined as a discussion. One side gets to make a statement and then the other side gets to address the issue presented and is expected to stay on topic.
In this case there is no single word to define reason, the phrase “let us reason together” is yâkach, yaw-kahh’; a primitive root; to be right (i.e. correct); reciprocal, to argue; causatively, to decide, justify or convict:—appoint, argue, chasten, convince, correct(-ion), daysman, dispute, judge, maintain, plead, reason (together), rebuke, reprove(-r), surely, in any wise.
The first word used is reciprocal, meaning a back and forth, each side gets to have a say to plead their case in determining how to decide the matter presented.
God gives the invitation and makes the first declarative; “you have sinned.”
Take the other side of this discourse. What do we have to say about that declarative statement?
Remember at this time that God has called you to come and discuss this matter. You did not initiate this conversation, God did. Before we can formulate our answer we must first take a measure of the one sitting on the other side of the table.
One option is to challenge the other side. “Who are you to define sin?”
“I am the God of the Universe who created you. I alone get to declare what is sinful.”
Do we challenge His authority? “Prove it!”
Proving a point of disagreement is a vital part of discourse. Anything that is stated as a declarative statement has to be backed up with some reasonable evidence from a reliable source.
“Look at me. Do you recognize me?”
At this point we are arguing against ourselves as to how we came to be in this discussion in the first place.
We cannot continue this discourse if we cannot answer the first basic question: how did I receive this invitation in the first place?
If you do not recognize God, you cannot have this discussion.