IBNHIBBAN 3634:
from Abū Ayyūb al-Anṣārī —
“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)
ابن حبّان ٣٦٣٤:
عن ابو ايوب الانصاري —
عَنْ رَسُولِ اللَّهِ ﷺ قَالَ «مَنْ صَامَ رَمَضَانَ وَأَتْبَعَهُ بِسِتٍّ مِنْ شَوَّالٍ فَذَلِكَ صَوْمُ الدَّهْرِ»