Comparing the socialists and the RSS activists, Kumar said while the former were rich in ideology, the latter were equipped with a strong organisation.
Addressing a function to mark the 82nd foundation day of Congress Socialist Party which was found in Patna, he made a call for all socialists to unite.
Kumar, who is also president of the JD(U), said he does not have any claim to the post of Prime Minister.
"I am not that fool," the chief minister, who played a crucial role in forming the Grand Secular Alliance in Bihar, said.
Kumar had played an important role in unification of splinter parties of erstwhile Janata Parivar under Samajwadi Party chief Mulayam Singh Yadav before Bihar poll but that did not yield any result.
"Socialists never paid attention to form a strong political organisation. Socialists should be cautious now," he said.
Social activist Medha Patkar, socialist leader and freedom fighter G G Parikh, general secretary of Hind Mazdoor Sabha Harbhajan Singh Sidhu, Rashtriya Sewa Dal's Sadashiv Magdum and former MP of Jammu and Kashmir Sheikh Abdul Rahman attended the function at Anjuman Islamia hall, where the Congress Socialist Party was formed 82 year ago.
Karnataka MLA B R Patil, social worker Sandeep Pandey and Bapu Hedushetty of Centre for Socialist study of Bengaluru, among others, were present in the function.
