Every dispute that is for the sake of Heaven, will in the end endure; But one that is not for the sake of Heaven, will not endure. Which is the controversy that is for the sake of Heaven? Such was the
controversy of Hillel and Shammai. And which is the controversy
that is not for the sake of Heaven? Such was the controversy of Korah and all his congregation 

Menahem Meiri (Catalonia, 1249–1306) explains this teaching in the following terms: The argument between Hillel and Shammai: In their debates, one of them would render a decision and
the other would argue against it, out of a desire to discover the truth, not out of cantankerousness or a wish to prevail over his fellow.  

An argument not for the sake of Heaven was that of Korach and his company, for they came to undermine Moses, our master, may he rest in peace, and his position, out of envy and contentiousness and ambition for victory. 

Bartenura : [with] the argument which is for the sake of Heaven, the purpose and aim that is sought from that argument is to arrive at the truth, and this endures; like that which they said, 'From a dispute the truth will be clarified,' and as it became elucidated from
the argument between Hillel and Shammai - that the law was like the school of Hillel.