A perceived insult by Marco Rubio fueled Gov. Chris Christie’s bombshell endorsement of Donald Trump, the New York Times reports.

Rubio placed a condescending call to ask for the governor’s backing after Christie dropped out of the presidential race. The 44-year-old candidate all but patted Christie, 53, on the head in a voicemail message, saying he “had a bright future in public service,” sources told the Times.

The message infuriated Christie, who blamed a Rubio-boosting super PAC for a spate of negative ads that dashed the governor’s White House hopes.

Watch Donald Trump tell Chris Christie to “Get in the plane and go home” during a campaign event.