After the tragedy of Karbala (in the year 61H / 680 CE), in which the Prophet Muhammad’s grandson Husayn was slaughtered along with many of his family members, the following lines of poetry were recited by Zaynab bint `Ali (Husayn’s sister) (according to another version it was Zaynab bint `Aqil, Husayn’s first cousin):

Tell me what you would say if the Prophet of God were to ask: 
What, O what have you done, O ye readers of God's Final Book? 
To the folk of my household, my dear kith and kin, after me? 
See now half of them captives and half drenched in blood lying slain. 
Is this what I deserve? Nay, aforetime I warned you, quite clear, 
Lest you later betray me, mistreating my own flesh and blood.

ماذا تقولون إن قال النبي لكم * ماذا فعلتم وأنتم آخر الأمم
بعترتي وبأهلي بعد مفتقدي * منهم أسارى ومنهم ضرجوا بدم
ما كان هذا جزائي إذ نصحت لكم * أن تخلفوني بسوء في ذوي رحمي

Abul-Aswad al-Du'ali, a close companion of `Ali ibn Abi Talib, 
responded upon hearing these words,
"We will say (to God): Our Lord, we have wronged ourselves, 
and if You do not forgive us and have mercy upon us, 
we will surely be among the losers. [Quran, 7:23]"
رَبَّنَا ظَلَمْنَآ أَنفُسَنَا وَإِن لَّمْ تَغْفِرْ لَنَا وَتَرْحَمْنَا لَنَكُونَنَّ مِنَ ٱلْخَـٰسِرِينَ

Sources: Tarikh Dimashq, Ansab al-Ashraf, Muruj al-Dhahab  with slight variations in the wording of the lines of poetry