The following 3 quotes are from page 244 of Imam Adh Dhahabi’s (D. 748AH) biography of Ibn Taymiyyah included in the compilation called, “From the Legacy of Shaikhul Islam Ibn Taymiyyah”, found here:
وله حدة قوية تعتريه في البحث حتى كأنه ليث حرب. أهـــ
“He had an acute harshness that would overcome him during debate, making him like a lion of war.”
وفيه قلة مداراة وعدم تؤدة غالبًا , والله يغفر له. أهـــ
“He often lacked congeniality and prudence. May Allah forgive him.”
وَقَدْ يُعَظِّمُ جليسه مرة ويهينه في المحاورة مرات. أهـــ
“He may honor his company once, yet disrespect them during debate repeatedly.”
Courtesy of Shaykh Abdur Rahman Sondalaani:
The Reality of ibn Taymiyya 