Supplication Prior to Dailiy Prayers

It has been narrated from Imam Sadiq (A.S) that Imam Ali (A.S) said to his followers: whoever says the proclamation for performing the prayer and recites this prayer before saying Allahu Akbar: 

يَا مُحْسِنُ قَدْ أَتَاكَ الْمُسِيءُ وَ قَدْ أَمَرْتَ الْمُحْسِنَ أَنْ يَتَجَاوَزَ عَنِ الْمُسِيءِ وَ أَنْتَ الْمُحْسِنُ وَ أَنَا الْمُسِيءُ فَبِحَقِّ مُحَمَّدٍ وَ آلِ مُحَمَّدٍ صَلِّ عَلَى مُحَمَّدٍ وَ آلِ مُحَمَّدٍ وَ تَجَاوَزْ عَنْ قَبِيحِ مَا تَعْلَمُ مِنِّي.

O’ the Beneficent, the wrongdoer has come to You and You have ordered the virtuous to forgive (the sins of) the wrongdoer and You are the virtuous and I am the wrongdoer; thus, for the sake of Muhammad and his Household, bless Muhammad and his Household and forgive the shameful thing You know of me. 

Then, God says: “O’ My angels! Witness that I forgave him and satisfied those whom he owes to”. 

Al-Balad Al-Amin and Al-Dar' Al-Hasseen, Text, p. 6

Bihar Al-Anwar (ed. - Beirut), vol. 81, p. 375

Misbah al-Mutahajjid and Silah al-Muta'abbidd, vol. 1, p. 73