Sunan an-Nasa'i, Volume 3, Book 24, Hadith 2956 (DarusSalam) ⓘ
It was narrated that Ibn Umar said: "Since I saw the Messenger of Allah touch it, I did not fail to touching the Stone whether it was easy or difficult."
أَخْبَرَنَا عِمْرَانُ بْنُ مُوسَى، قَالَ حَدَّثَنَا عَبْدُ الْوَارِثِ، قَالَ حَدَّثَنَا أَيُّوبُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ مَا تَرَكْتُ اسْتِلاَمَ الْحَجَرِ فِي رَخَاءٍ وَلاَ شِدَّةٍ مُنْذُ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَسْتَلِمُهُ .
also referenced under: Hadith 2953 (Reference) & Book 24, Hadith 0 (In-Book)