IBNMAJAH 1716:
from Abū Ayyūb —
“Whoever fasts Ramadan then follows it with six days of Shawwal, it is as if he fasted for a lifetime.”
ابن ماجة ١٧١٦:
عن ابو ايوب —
قَالَ رَسُولُ اللَّهِ ﷺ مَنْ صَامَ رَمَضَانَ ثُمَّ أَتْبَعَهُ بِسِتٍّ مِنْ شَوَّالٍ كَانَ كَصَوْمِ الدَّهْرِ