364.Narrated Abu Huraira (Allah be pleased with him): I said: O Allah's Apostle (peace be upon him) !, "Who will be the luckiest person, who will gain your intercession in the Day of Resurrection?" Allah's Apostle (may the blessings and peace of Allah be) upon him) said: O Abu Huraira! "I have thought that none will ask me about it before you as I know your longing for the (learning of) Hadiths. 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 "None has the right to be worshipped but Allah."
(Sahih Al-Bukhari Vol 1).
(Dr. Muhammad Muhsin Khan et.al.).