I recently watched your lecture about the narrations from Karbala, and in the lecture you mentioned that the Quran talks about Christians that were burned in a ditch by an unjust king in surah Barooj. I looked in my tafsir books at home but I did not see the same tafsirs (I saw 3 possible different narratives) and I was wondering what your source was so that I may read it as well.

Tafsirs such as Al-Amthal mention this. The hadith source that we have for it is Tafsir al-Qummi. You may read it here: