Actually, He did establish new rules.
He gave us a new commandment in John 13:34.
He established a new commandment in 1 Cor 13:37, related to what should happen in a church service.
In Acts 17:30, He now commands all men, everywhere to repent.
In 1 John 3:23, the command is given: "And THIS is his command: to believe in the name of his Son, Jesus Christ, and to love one another as he commanded us.
I considered those, but “love” and “repent” strike me as commands on how to conduct ourselves. I was reading ‘establish rules’ in the sense of Leviticus.