حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا قَضَى طَوَافَهُ بِالْبَيْتِ وَرَكَعَ الرَّكْعَتَيْنِ وَأَرَادَ أَنْ يَخْرُجَ إِلَى الصَّفَا وَالْمَرْوَةِ اسْتَلَمَ الرُّكْنَ الأَسْوَدَ قَبْلَ أَنْ يَخْرُجَ ‏.‏

Yahya related to me from Malik that he had heard that when theMessenger of Allah, may Allah bless him and grant him peace, hadfinished his tawaf of the House, prayed two rakas, and wanted to go toSafa and Marwa, he would salute the corner of the Black Stone beforehe left. Translation Not Available

Book Ref: Muwatta Imam Malik Book 20 Hadith 816
Web Ref:  Muwatta Imam Malik Book 20 Hadith 113