Ibn Taymiyyah mentioned that acting upon a weak hadith was not stated by any of the Imams, but Imam Ahmad
Machine translationRead the Arabic original
Question:
And Honorable Shaykh, may Allah grant you success, according to Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him), no one of the Imams said that it is permissible to make something obligatory or recommended based on a weak hadith. The question is: Is it not among the principles of Imam Ahmad (may Allah have mercy on him) that we have studied, that if no evidence is found for an issue except a very weak hadith, then it is used as evidence for that issue?
Answer:
It appears that he wrote the question before hearing the end of the statement. I heard that what Ahmad meant by a weak hadith is a hasan (good) hadith; a hasan hadith is not what he intended by weak, which is below hasan. So with this, the problem is resolved. Yes.
And Honorable Shaykh, may Allah grant you success, according to Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him), no one of the Imams said that it is permissible to make something obligatory or recommended based on a weak hadith. The question is: Is it not among the principles of Imam Ahmad (may Allah have mercy on him) that we have studied, that if no evidence is found for an issue except a very weak hadith, then it is used as evidence for that issue?
Answer:
It appears that he wrote the question before hearing the end of the statement. I heard that what Ahmad meant by a weak hadith is a hasan (good) hadith; a hasan hadith is not what he intended by weak, which is below hasan. So with this, the problem is resolved. Yes.
Source
قناة «العلامة الدكتور صالح الفوزان»، [707 /1350] ذكر ابن تيمية أن العمل بالحديث الضعيف لم يقله أحد من الأئمة، ولكن الإمام أحمد.. — youtube.com
The Arabic text is a machine transcription of the audio recording.