حَدَّثَنَا وَكِيعٌ، عَنْ هِشَامٍ، عَنْ أَبِيهِ، أَنَّ عُمَرَ
رَضِيَ اللَّهُ عَنْهُ أَتَى الْحَجَرَ فَقَالَ إِنِّي لَأَعْلَمُ أَنَّكَ حَجَرٌ لَا تَضُرُّ وَلَا تَنْفَعُ وَلَوْلَا أَنِّي رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُقَبِّلُكَ مَا قَبَّلْتُكَ قَالَ ثُمَّ قَبَّلَهُ
I know that you are only a stone and you cannot cause harm or bring benefit. Were it not that I saw the Messenger of Allah (sallallahu alayhi wa sallam) kiss you, I would not have kissed you. Then he kissed it.
Musnad Ahmad 359, Book 2, Musnad `Umar b. al-Khattab (ra), Hadith 282. 1 min read