Ibrahim (al-Nakha'i) said: If I had been among those who killed Husayn bin Ali, and then I had been forgiven and then admitted into Paradise, I would be ashamed to pass before the Prophet (peace and blessings be upon him) and have him look at my face.
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2816