"Even if I win, Rugby Australia can appeal", he said.
"YOU are in a fight that YOU chose to be in after YOU broke the terms of YOUR contract", mitchell posted on Twitter.
"And it'll send the message once and for all: If he wants to continue to use his profile and platform to preach hate, Israel Folau picked the wrong sport, because intolerance such as his will never be tolerated in rugby", he added.
Folau's biggest claim in his first interview with 2GB's Alan Jones on Friday morning was that his legal pursuit of Rugby Australia is not being motivated by money in any way - and he is being driven purely by the principles of his Christian faith.
Folau, whose contract with the Australian union's governing body was terminated in May over homophobic social media posts has set up a GoFundMe page to raise the NZ$3.15 million says he needs to cover costs in his bid to seek reinstatement. His dismissal followed earlier incendiary remarks about the gay community a year ago, for which he escaped sanction. "I do not believe that it is fair or right that I be punished for my religious beliefs", he said.
There is nothing stopping Folau from taking more money than the cost of his legal fees.
'I believe that sharing the Bible is an act of love and compassion'.
Asked on Sydney radio 2GB if RA had a social media clause in his contract that would have prohibited him from speaking about his faith, Folau said "no, absolutely not".
He believes he has done that while standing "up for the word of God".
"There's things that the bible might go against, things that people are doing, but from my perspective, I'm all about doing that from a place of love and believing in the bible that if people have an opportunity to hear that so that if they do choose to repent and turn away from that then they have an opportunity to be in heaven one day, which is what I long for people to do". "I have the fight of my life on my hands and every little bit will help".
Folau says he and wife Maria, an global netball player, have already spent more than $100,000 dealing with RA's internal tribunal processes.
Folau, whose lucrative contract with Rugby Australia and his team the NSW Waratahs was torn up in May after he posted an Instagram post suggesting gay people and other "sinners" will go to Hell, shared a video on the crowdfunding site saying the legal stoush is a battle for all religious Australians.
"In response, Rugby Australia have already said that they will "divert significant resources" to fight me in court", Folau said in his statement.
Last year the 73-test star signed a four-year deal with RA worth an estimated A$5 million and has been one of Australian rugby's highest paid players since he crossed codes in 2013.