"We had already told the BJP about our apprehensions. We cannot have a man who is a divisive figure. Our diverse country needs a man who can unify," Kumar told CNN-IBN.
JD(U) broke its 17-year-old alliance with the NDA in the wake of BJP anointing Modi as chief of the party's election campaign committee for the 2014 Lok Sabha polls.
"A personality-oriented atmosphere has been created in BJP now. All the discussions now centre around that," Kumar said.
"There should not be polarisation. The polarising figure should not overshadow the issues confronting the country...Can the development model of a developed state like Gujarat become the model for the entire country? There are many backward regions in the country," he said.
Asked about his 2003 statement praising Modi, Kumar said, "After the 2003 statement, there was 2005 election in Bihar. Why did not they call him to Bihar? Why did not they ask him to come in 2009?...I have also talked about what happened in 2002 in that speech.