It is narrated from a Sheikh who met the Prophet (peace be upon him) that once I set out on a journey with the Prophet (peace be upon him). The Prophet (peace be upon him) passed by a man who was reciting Surah Al-Kafirun. The Prophet (peace be upon him) said: "He has become free from shirk." Then he saw another man who was reciting Surah Al-Ikhlas. The Prophet (peace be upon him) said: "Because of its blessing, Paradise has become obligatory for him."
Hadith Referenceمسند احمد / مسند المدنيين رضي الله عنهم اجمعين / 16605
Hadith Gradingحکم دارالسلام:حديث صحيح، المسعودي مختلط، وسماع أبى النضر منه بعد اختلاطه، وقد توبع