Bismillaahir Rahmaanir Raheem
Umar (may Allâh be pleased with him) saw Ziyad bn Hufayr put on a pallium (a type of cloth worn specifically by the Christians and Jews) and allow his moustache grow heavy, he did not respond to his greeting until he removed the pallium and reduced the moustache. The incident was recorded by Abu Nuaym in Hilyatul-Auliyaa.
[Today, Muslims see no problem with a Muslim man who knowingly shaves his beard].
Ibn Umar (may Allâh be pleased with him) deserted a man whom he told should stop throwing pebbles around the place, having told him that the Messenger of Allâh (salAllâhu alahy wa sallam) prohibited the act. The man did not listen and Ibn Umar (may Allâh be pleased with him) said, ‘I will never talk to you again.’ Recorded by al-Haakim.
Ibn Mas’ood (may Allâh be pleased with him) saw a man laughing as a funeral passed by, he said, ‘I will not talk to you again.’ Al-Imâm Ahmad recorded it in Az-Zuhd.
Al-Qaadee Aboo Ya’laa (may Allâh bestow mercy on him) said, ‘The Companions and the Taabi’oon agreed as to severing ties from the people of Bid’ah.’ There is a similar statement from al-Imâm Al-Baghawee, al-Ghazalee and Ibn Abdil-Barr; they all say there is a consensus over that.
Ibn Umar (may Allâh be pleased with him) sent a message to the people denying predestination as thus, ‘I am free from you and you are free from me.’ Recorded by Muslim.
Al-Fudayl bn Iyaad (may Allâh bestow mercy on him) said, ‘Be wary of whoever sits with a person of Bid’ah; such will lack wisdom. I love that there is s fortress of steel between me and a person of Bid’ah. That I eat with a Jew or a Christian is more loving to me than I sit with a person of Bid’ah.’ See Shar’hus-Sunnah 130.
He (may Allâh bestow mercy on him) also said, ‘Whoever leads a person to an innovator has deceived Islam. Be wary of sitting with people of Bid’ah, they dissuade from the truth.’
Abdullah bn al-Mubarak (may Allâh bestow mercy on him) said, ‘Be wary of sitting with an innovator.’
Sufyaan Ath-Thauree (rahimahuLlaah) said, ‘Whoever listens to a person of Bid’ah has left the protection of Allâh. Such will be made to rely on it (i.e. that Bid’ah).’
Al-Imâm Al-Laalikaa’ee (may Allâh bestow mercy on him) brought a report from Aboo Zur’ah (may Allâh bestow mercy on him) that he said, ‘I did see Sabeegh bn Isr (the one beaten by Umar for asking unnecessary questions about the Qur’aan) in Basrah going about like a stray donkey. Anytime he came to a sitting of knowledge, the people there would stand and leave him. If he managed to sit where he was not known, those who knew him (from the other sitting) would call out: ‘See the one beaten by Ameerul-Mu’mineen.’’
Ibn Abee al-Jauzaa (may Allâh bestow mercy on him) said, ‘That I sit close to monkeys and pigs is more beloved to me than I sit close to any of them (i.e. people of innovations).’
Ibn Taawus (may Allâh bestow mercy on him) once covered his ears with his fingers when he heard a Mu’tazilee speaking.
Abdur-Razzaaq (may Allâh bestow mercy on him) forbade people to listen to Ibrâhîm bn Abee Yahya al-Mu’tazilee. He said, ‘The heart is weak and the Deen is not about who dominates (in argumentation).’
Younus bn Ubayd (may Allâh bestow mercy on him) used to say, ‘Do not sit with a ruler nor an innovator.’
Yahya bn Abee Katheer (may Allâh bestow mercy on him) said, ‘When you meet an innovator on a route, take another road.’
Ibrâhîm bn Maysarah (may Allâh bestow mercy on him) said, ‘Whoever honours an innovator has taken part in destroying Islam.’
Abdullah ibn al-Mubarak (may Allâh bestow mercy on him) forsook Abdullah bn Umar As-Sar’khasee for a period of time because the latter ate with a person of Bid’ah.
Al-Hasan al-Basree (may Allâh bestow mercy on him) said, ‘Do not sit with people of desires nor argue with them nor listen to them.’
Aboo Qulaabah (may Allâh bestow mercy on him) said, ‘Do not sit with hem, do not mix with them. I cannot guarantee that they will not drag you into their misguidance and make many of what you have known about the Deen confusing to you.’
Al-Imaam Maalik (may Allâh bestow mercy on him) would not make Tasleem to the people of bid’ah. Ibn Daqeeq al-‘Eed (may Allâh bestow mercy on him) commented on that, ‘That was meant to teach them a lesson, and serve as his disavowal of them.’
Al-Khattaabee (may Allâh bestow mercy on him) said, ‘Forsaking people of desires and innovations will remain as long as they do not make their repentance and return to the truth apparent.’
Click the link to read the summary of the whole article from the work of Ash-Shaykh Bakr Aboo Zayd, hajrul-mubtadi.