Amongst the last things one should say when doing the tashahud before giving the salaams
ثُمَّ يَكُونُ مِنْ آخِرِ مَا يَقُولُ بَيْنَ التَّشَهُّدِ وَالتَّسْلِيمِ ”
اللَّهُمَّ اغْفِرْ لِي مَا قَدَّمْتُ وَمَا أَخَّرْتُ وَمَا أَسْرَرْتُ وَمَا أَعْلَنْتُ وَمَا أَسْرَفْتُ وَمَا أَنْتَ أَعْلَمُ بِهِ مِنِّي أَنْتَ الْمُقَدِّمُ وَأَنْتَ الْمُؤَخِّرُ لاَ إِلَهَ إِلاَّ أَنْتَ ” .
“Forgive me of the earlier and later, open and secret (sins), and that where I made out of transgression and that You know better than I. You are the First and the Last. There is no God worthy to be worshipped except You.”
Reported by Muslim.
Note: Al-Imam Nawawi rahimahullah saw this du’a to be specific for the night prayer. However, other narrations and wordings have come to show one could read this supplication as well in the five daily prayers. Being this is the case, some of the scholars have mentioned this du’a amongst the du’as that could be read in the last tashahud.
AbdulFattaah Bin Uthman