Allah Humma Rabba Shahre RamadhanAl-Kafami, in al-Balad al-Amin and al-Misbah has quoted the Kitab al-Ikhtiyar of Sayyid ibn Baqi that if one recites the following supplication everyday in Ramazan, Allah (swt) will forgive the sins of forty years of his age.
اللّهُمّ رَبّ شَهْرِ رَمَضَانَ
all¡humma rabba shahri ramadhan
الّذِي أَنْزَلْتَ فِيهِ القُرْآنَ،
alladhy anzalta feehi alqur’an
وَافْتَرَضْتَ عَلَى عِبَادِكَ فِيهِ الصّيَامَ،
waftaradhta `al¡ `ib¡dika feehi ssiy¡ma
ارْزُقْنِي حَجّ بَيْتِكَ الحَرَامِ
urzuqny hajj baytika alharam
فِي هذَا العَامِ وَفِي كُلّ عَامٍ،
fee hadh¡ al`aami wa fee kulle `aamin
وَاغْفِرْ لِيَ الذّنُوبَ العِظَامَ
waghfir liya aldhdhunuba al`izama
فَإنّهُ لا يَغْفِرُهَا غَيْرُكَ
fa’innahu l¡ yaghfiruh¡ ghayruka
يَا ذَا الجَلالِ وَالإكْرَامِ.
ya dhaljal¡li wal-ikrami
