1) Words and actions should help unite, and not divide, the people of our various nationalities.
2) They should be beneficial, and not harmful, to socialist transformation and socialist construction.
3) They should help to consolidate, and not undermine or weaken, the people’s democratic dictatorship.
4) They should help to consolidate, and not undermine or weaken, democratic centralism.
5) They should help to strengthen, and not discard or weaken, the leadership of the Communist Party.
6) They should be beneficial, and not harmful, to international socialist unity and the unity of the peace-loving people of the world.
Of these six criteria, the most important are the socialist path and the leadership of the Party.
(On the Correct Handling of Contradictions Among the People, February 27, 1957, 1st Pocket Edition, Pages 57-58)