Gandhinagar, Feb 20 (ANI): Continuing with the war of words with Finance Minister P Chidambaram, Narendra Modi said that the Congress minister was working very hard to boost the country’s revenues by imposing service tax on his speeches. Modi was addressing a seminar on 'Financial Services - a key driver for economic growth in Gandhinagar where he took pot shots at Chidambaram. Earlier, Chidambaram has said that he does not want to indulge in a class 8 schoolboy debate after Modi criticised the interim budget.