Midrash su Isaia 32:5

(Ib. b) "And when he reached the passage, Thou mayest not," etc. We are taught in the name of R. Nathan: "At that moment when the sages tried to pacify King Agrippa, Israel deserved a punishment, because they flattered King Agrippa." R. Simon b. Chalafta said: "Since the above flattery had taken place, justice became perverted and man's actions became corrupt, so that no man can say to his associate, 'My deeds are better than yours.'" R. Juda b. Ma'araba, and according to others R. Simon b. Pazzi said: "One is permitted to flatter the wicked in this world as it is said (Is. 32, 5) The vile person shall be no more called liberal nor the churl said to be noble. This refers to the future world, hence in this world one is permitted to do so." R. Simon b. Lakish said: "The above may be inferred from the following (Gen. 33, 10) It is as though I had seen the face of an angel, and because thou hast received me kindly." This will differ with R. Levi's statement, for R. Levi said: "Unto what may the incident of Jacob and Esau be likened? Unto a man who invited his friend to a banquet. The guest being aware that the host desired to kill him [was afraid that poison might be in the food] passed a remark that the dish tastes like the dish he eats in the Royal house. His enemy said to himself: 'Since he is known to the Royal family, I am afraid to kill him.' In like manner was it with Jacob, when he mentioned the face of an Angel, it was for the purpose of frightening Esau he should not kill him."