“Whoever fasts Ramadan then follows it with six days of Shawwal, it is as if he fasted for a lifetime.” (Using translation from Ibn Mājah 1716)

قَالَ رَسُولُ اللهِ ﷺ «مَنْ صَامَ رَمَضَانَ وَأَتْبَعَهُ بِسِتٍّ مِنْ شَوَّالٍ فَهُوَ صِيَامُ الدَّهْرِ»