"Singh's remarks that he would fight the battle in the court and also in the court of the people amounted to showing disrespect to judiciary...He should honour the court order," Jain told a press conference here.
Singh has to pass through legal process for absolving himself of the graft charges, he said.
A five-time chief minister of Himachal Pradesh, 78-year-old Singh resigned yesterday as union Minister for Micro, Small and Medium Enterprises "on moral grounds".
His decision came a day after the Himachal court framed charges of corruption and criminal misconduct against him and his wife Pratibha Singh in a 23-year-old case, saying there was sufficient evidence to proceed against them.