The preamble he wrote 

  The first session of the 10th Supreme People’s Assembly of the DPRK took place in Pyongyang in September 1998.
Days before the session an official received the draft of the preamble of the Socialist Constitution of the DPRK which had been prepared by Chairman Kim Jong Il. Reading it word by word he was quite moved. At the moment he got a phone call from the Chairman.
The Chairman asked him if he had received the draft of the preamble of the Constitution. Then he said that although the Constitution adopted in 1972 had no preamble he put a preamble in it to stipulate the immortal achievement of President Kim Il Sung. With the preamble the Constitution got a clear quality befitting its mission.
The official was reminded of the Chairman’s painstaking effort to develop the Socialist Constitution of the DPRK, which legalizes the President’s Juche-oriented idea and achievement of state building, into Kim Il Sung Constitution. It touched him heartily. He knew that the preamble was just a thing that the Chairman alone could do who was endowed with the loyalty to the President and the sense of moral obligation at the highest possible level.
With the preamble written by the Chairman, the Socialist Constitution of the DPRK became more ennobling as it was dedicated to the eternal life of the President.