Reward for fasting Ramadan plus six days of Shawwal amounts to fasting a lifetime

[AI] That the Messenger of Allah ﷺ said: "Whoever fasts Ramadan, then follows it with six days of Shawwal, it is like fasting a lifetime."

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ: «مَنْ صَامَ رَمَضَانَ ثُمَّ أَتْبَعَهُ سِتًّا مِنْ شَوَّالٍ كَانَ كَصِيَامِ الدَّهْرِ».

I heard Messenger of Allah ﷺ saying like this.

أَخْبَرَنَا أَبُو أَيُّوبَ الأَنْصَارِيُّ ؓ قَالَ سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ بِمِثْلِهِ

Abu Ayyub reported a hadith like this (through another chain of transmitters).

سَمِعْتُ أَبَا أَيُّوبَ ؓ يَقُولُ قَالَ رَسُولُ اللَّهِ ﷺ بِمِثْلِهِ