The Book of Pilgrimage
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَابْنُ، نُمَيْرٍ جَمِيعًا عَنْ أَبِي خَالِدٍ، - قَالَ أَبُو بَكْرٍ حَدَّثَنَا أَبُو خَالِدٍ الأَحْمَرُ، - عَنْ عُبَيْدِ اللَّهِ، عَنْ نَافِعٍ، قَالَ رَأَيْتُ ابْنَ عُمَرَ يَسْتَلِمُ الْحَجَرَ بِيَدِهِ ثُمَّ قَبَّلَ يَدَهُ وَقَالَ مَا تَرَكْتُهُ مُنْذُ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَفْعَلُهُ .NAfi' (Allah be pleased with him) reported:I saw'lbn 'Umar (Allah be pleased with them) touching the Stone with his hand and then kissing his hand. and he said: I have never abandoned it since I saw Allah's Messenger (way peace be upon him) doing It
From Sahih Muslim, whose reports the scholars accept as authentic.