A man said, "Abu Abd al-Rahman, I see that you only touch these two corners."He replied, "I heard the Messenger of Allah ﷺ say, 'Touching them wipes away sins.' And I heard him say, 'Whoever circumambulates seven times, it is equivalent to freeing a slave.'"
أن رجلا قال: يا أبا عبد الرحمن ما أراك تستلم إلا هذين الركنين؟ قال: إني سمعت رسول الله ﷺ يقول: إن مسحهما يحطان الخطيئة. وسمعته يقول: من طاف سبعا فهو كعدل رقبة.
Nasai narrated it (2919) from Qutayba, who said, Hammad narrated to us, from Ataa, from Abdullah bin Ubayd bin Umayr, and he mentioned it.The unnamed man is Ibn Umayr's father, as stated explicitly in other narrations. Ataa is Ibn Saaib, who became confused in his later years. Its chain of transmission is sahih, since Hammad is Ibn Zayd, who was among those who heard from Ataa before his confusion set in. Abu Abdul-Rahman is Abdullah bin Umar.