"I dare him to put that motive on the table in proper fact," said Moseneke in the dead quiet room as the Judicial Service Commission (JSC) held a preliminary inquiry into a Constitutional Court complaint against Hlophe.
The Constitutional Court judges had complained that Hlophe might have improperly tried to influence a judgment on President Jacob Zuma that they were working on.
Hlophe had counter-complained that the judges publicised their complaint before hearing his side of the story.
Moseneke explained to the hearing in Braamfontein on Thursday that he had returned from a sabbatical to be informed by Acting Chief Justice Kate O'Regan of an alleged improper approach by Hlophe to Acting Justice Chris Jafta and Justice Bess Nkabinde.
Moseneke said in line with his oath of office he was obliged to look at the complaint.
He had to consider the facts and decided it was reportable to the JSC.
He said it was unfortunate that Hlophe had raised a political motive, after Hlophe referred to the fact that only the Democratic Alliance had received a statement on the matter before Hlophe was given a chance to respond.
Moseneke said the court's email list was compiled of people who ask to be put on it.
He considered Hlophe's "attack" on the chief justice as very serious.
The Constitutional Court judges had no intention of having Hlophe impeached, said Moseneke. He himself hoped that Hlophe's career would flourish as he was still young.
Earlier Nkabinde said that she "snapped" when Hlophe began discussing the Zuma case, and told him that he should not. She had been warned by Jafta that the subject might come up so she stopped him as soon as he broached the subject.
She said that she does not even discuss cases with her colleagues at the court while she is writing them.
Under cross-questioning, she said the issue that Hlophe had said must be "decided properly" referred to the matter of privilege, which she had written a note on.
"He didn't say 'decided on in this particular way'," she said.
Moseneke said they had decided an independent body should hear the complaint and make a finding on it.
Jafta and Nkabinde were reluctant to go ahead with a complaint by themselves, so the whole court decided to lodge a complaint.
"They being our colleagues, as we heard them, we believed them as we do now and we accept what they tell us."
He said it was up to the JSC to decide whether it was true or not.
"Once we had heard what happened, we couldn't pretend we did not hear it," he said.
He said they had made the matter public to avoid rumours from circulating.