Imam Ahmad said:

The partaker in Kalaam [1] will never be successful at all, and you will not see a person looking into [the science of] Kalaam except that in his heart is a defect [or fault] [2].


[1] Ilm Al-Kalaam is the discipline of seeking theological principles through dialectic and philosophical arguments.

[2] Ihyaa’ ‘Uloom Ad-Deen (1/124)

قال الإمام أحمد: لا يفلح صاحب الكلام أبدا, ولا تكاد ترى أحدا نظر في الكلام إلا وفي قلبة دغل.ـ