"As there is a great likelihood that the debate on 'How Malaysia became a global kleptocracy and how we can become a leading nation of integrity' between Najib and myself could be turned into a Malay vs Chinese conflict... I have decided not to proceed with the debate with Najib," he said in his blog post on Thursday (May 23).
Lim noted that the debate between them should be "the battle against corruption, abuses of power and criminal conduct like money laundering", which is not a racial or religious issue, but an issue of good values and good governance.
The Iskandar Puteri MP said in the past 48 hours, he had received advice from many Malaysians, even those overseas, urging him not to debate with Najib.
Some of the advice include that Najib has nothing to lose, the people cannot see any benefit from the debate and that it can cause more harm than good.
Lim acknowledged that his decision will be greeted "with tempests of allegations that (he is) a coward".
"My 53 years of politics is an open book for Malaysians to judge whether I am a coward or not, and I am always prepared to subject myself to the judgment of Malaysians.
"However, there is one thing I will not compromise – the higher interests of the nation and Malaysians," he added.