A man came to the Messenger of Allah ﷺ and said, "I love this surah, Say, He is Allah, the One."The Messenger of Allah ﷺ replied, "Your love for it has admitted you into Paradise."
حدثنا أبو النضر حدثنا المبارك عن ثابت البناني
جاء رجل إلى رسول الله ﷺ فقال إني أحب هذه السورة قل هو الله أحد فقال رسول الله ﷺ حبك إياها أدخلك الجنة
Its isnad is sahih. Abu Nadr is Hashim bin Qasim, and Mubarak is Ibn Fadala, who is truthful. He used to practice tadlis, but he explicitly stated that he heard directly from Thabit in the following hadith, so this should be taken as direct hearing according to the position of Muslim.The hadith was narrated by Bukhari 1/197, in the book of adhan, chapter on combining two surahs, and by Tirmidhi 5/169, number 2901, who said, hasan gharib sahih, and by Darimi 2/553, number 1435. Hakim declared it sahih 1/240, and Dhahabi agreed with him.