Brethren, I write no new commandment unto you, but an old commandment which ye had from the beginning. The old commandment is the word which ye have heard from the beginning. – 1 John 2:7
John was pretty clear. He wasn’t writing about anything new. It wasn’t anything that the believers had not already heard, either directly from Jesus or quoted by one of the followers who had walked with Him during His earthly ministry.
There was already an “old commandment” and that was “no new commandment.” It all was the same.
Nothing was new.
Jesus said what needed to be said. He said it all from the onset of His ministry. He continued with it throughout His ministry. He wrapped up His ministry with the same thing.
His disciples and apostles were to continue in what He taught them from the beginning. New followers were to do so also. No one was to add anything to it. No one was to compel others to get circumcised or recognize new moons or other feasts to become at one with Christ. All that it took was a faithful belief in Him as the Son of God, the Savior, and the propitiation of our sins.
Nothing was added.