Nahj al-Balāgha
Hadith 2008وَالرَّابِعُ: أَنْ تَعْمِدَ إِلَى كُلِّ فَرِيضَةٍ عَلَيْكَ ضَيَّعْتَهَا فَتُؤَدِّيَ حَقَّهَا.
the fourth is to fulfil every obligation which you ignored (in the past) so that you may now do justice with it;