It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When you see so-and-so delivering a sermon on my pulpit, kill him."
Imam Ibn Abi Shaybah recorded this report in his al-Musannaf; its chain contains the narrator Mujalid bin Sa'id, who is da'if (weak) according to the majority of hadith scholars, and this report is technically munkar (rejected) and not established.
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الفتوح / 4433
Hadith Gradingمحدثین:إسناده موضوع
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :إسناده موضوع » «انفرد به المصنف من هذا الطريق»