Imām al-Shāṭibī writes:
“Rabies has some resemblance with an infectious disease. The root cause of rabies is found in a dog and then when the dog bites someone he becomes similar to it, and is not able to part from it in most cases without dying. The heretic (mubtadi‘) is the same: when he presents his view and doubt to another, he is rarely safe from its harm. In fact, he either falls into his ideology with him and becomes part of his group or it seeds a doubt in his heart that he wants to part from but is unable. This is different from all other sins…What proves this notion has occurred in reports [from the Salaf], as the pious Salaf forbade sitting with and speaking with them and listening to their speech and were strict on this…From them is what is reported from Ibn Mas‘ūd (RA) that he said: ‘Whoever wishes to honour his dīn, he must avoid mixing with the ruler and sitting with people of false ideologies, since sitting with them more strongly attaches [a person] than scabies.’” (al-I‘tiṣām)