Narrated Abû Huraira رضي الله عنه : I said “Allâh’s Messenger! Who
will be the luckiest person, who will gain your intercession on the Day of
Resurrection?” Allâh’s Messenger صلى الله عليه وسلم said: O ‘Abu
Huraira! I have thought that none will ask me about it before you as I know your
eagerness to (learn) the Ḥadîth. The luckiest person
who will have my intercession on the Day of Resurrection will be the one who
said sincerely from (the bottom of) his heart
Lâ ilahâ ill-Allâh (none has the
right to be worshipped but Allâh).”
Source: Summarized Ṣaḥîḥ Al-Bukhâri, under the Chapter 23. Eagerness to (learn) the Ḥadith., page 96, Ḥadith no. 85, Translated by Dr.Muhammad Muhsin Khan