"Had it been possible to remove a chief minister from power by collecting a few people in Gandhi Maidan... Who can stay in that seat," Kumar said at a public meeting here.
He, however, did not take the name of "Parivartan rally" organised by the RJD on May to remove NDA from power in Bihar.
"He has become unemployed and to attract media attention he is uttering derogatory things against opponents," Kumar said.
The rally was also addressed by rebel JD(U) MP Rajiv Ranjan Singh Lallan, Water Resources Minister Vijay Chaudhary and Roads Construction Minister and State NDA convener Nand Kishore Yadav.