"All faiths challenge us to be our best selves. It is one world and one for all. Now see you in the Octagon."
Two weeks ago, the twice Ultimate Fighting Championship title-holder sent shockwaves around the sporting world by saying he was retiring on Twitter.
The announcement drew plenty of scepticism, given it came only hours after McGregor told an American TV chat show that he was in negotiations for a fight in July.
A previous "retirement" announced by McGregor in 2016 lasted a matter of days.
The conciliatory tone of McGregor's tweet was at odds with an earlier string of abusive posts targeting Khabib Nurmagomedov, the Dargin who beat him in a fourth-round lightweight title fight in October.
McGregor has made no secret of his desire for a re-match.
"Don't be scared of the rematch you little scurrying rat. You will do what you are told like you always do," he tweeted on Wednesday.
McGregor also tweeted - then deleted - a number of derogatory posts about Nurmagomedov's wife.
Nurmagomedov also returned fire, calling McGregor a "rapist" on Twitter.
UFC President Dana White said in a statement that the online exchanges had become "unacceptable" and that he was reaching out to both camps to defuse the tension.
Neither McGregor nor Nurmagomedov have had another fight since, with both serving suspensions for an ugly brawl that erupted after their match in Las Vegas.
Boasting massive global recognition, McGregor wields considerable negotiating power over the UFC and pundits have speculated his retirement announcement was merely a ploy in a long battle to secure an ownership stake in the popular cage-fighting series.
"He's stuck on this thing where he wants a piece of the ownership and if you look at basketball, Michael Jordan didn't own a piece of the league," White told 8 News Now, a Las Vegas broadcaster, this week.
"I think there's other ways that we can make him happy."
American media have also speculated McGregor is in dispute with White over his ability to headline a card with no title on the line.
McGregor is said to need a fight or two to re-establish himself as a title contender to burnish his reputation and reinforce his clout as a pay-per-view draw.
(Reporting by Ian Ransom; Editing by Peter Rutherford/Sudipto Ganguly)
