"If there are bhikshus, bhikshunis, upasikas, upasikas, who put forth coarse, evil words and blaspheme the True Dharma, and creating this grave karma, never repent and have no penitence in their minds.... in that True Dharma they never have the mind to guard, spare, erect or establish but disparage, attack, slight and belittle and have many errors and faults in their words.... these also one names, 'heading towards the way of the icchantikas.' Only excluding classes of icchantikas such as these, if one donates to the remaining ones, it is to be praised" (Great Parinirvana Sutra 10: T.12.425a-b).
"If they are blasphemers, one ought not to abide together with them and likewise not approach and be intimate with them; if one approaches and is intimate and abides together with them, at once one heads toward the Avici Hell" (Jurinkyo (Sutra of Ten Wheels), "Chapter of the Multitude of Good Appearances" (T.13.704b, cited at Nambu Rokuro dono gosho, STN, v. 1, 487; Chu Hokekyo, v. jo, 2-79).
"Although nourishing (yashinau) the monks of the various sects of the Tendai, Shingon, and others of the present age outwardly appears, indeed, to be good [karmic] roots, inwardly it is a great evil surpassing even the Ten Evils and Five Rebellious [Sins]" (Chie bokoku gosho, STN, v.2, 1130).
"Only one should exclude and put away the blasphemous offerings of those of the Shingon, Zen Sect, Nembutsu and so on. For example, they are like adhering to and reverencing the Emperor Shakra [King of the Devas or Gods] while exalting and esteeming the asuras [the enemies of the Gods]"(Jomyo shonin gohenji, STN, v. 2, 1300).