ʿUmar came near the Black Stone and kissed it and said "No doubt, I know that you are a stone and can neither benefit anyone nor harm anyone. Had I not seen Messenger of Allah ﷺ kissing you I would not have kissed you."  

إِنِّي أَعْلَمُ أَنَّكَ حَجَرٌ لاَ تَضُرُّ وَلاَ تَنْفَعُ وَلَوْلاَ أَنِّي رَأَيْتُ النَّبِيَّ ﷺ يُقَبِّلُكَ مَا قَبَّلْتُكَ