It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) performed Tawaf of the Ka'bah while riding a camel, and whenever he passed by the Black Stone, he would point towards it with whatever (stick, etc.) he had in his hand and say "Allahu Akbar."
Hadith Referenceسنن دارمي / من كتاب المناسك / 1883
Hadith Takhrijاس روایت کی سند صحیح اور حدیث متفق علیہ ہے۔ دیکھئے: [بخاري 1607] ، [مسلم 1272] ، [ترمذي 865] ، [ابن حبان 3825]
Brief Explanation
(Commentary on Hadith 1882)
From this hadith, it is established that the Messenger of Allah sallallahu alayhi wa sallam performed tawaf (circumambulation) on a mount, pointed towards the Black Stone (Hajar al-Aswad) with a staff, and said "Allahu Akbar." This is also the position of Imam Shafi'i and Imam Ahmad rahimahumullah, that performing tawaf while mounted is permissible in case of necessity. And when kissing the Black Stone or pointing towards it, the one performing tawaf should say: «بِسْمِاللّٰهِوَاللّٰهُأَكْبَرُاَللّٰهُمَّإِيْمَانًابِكَوَتَصْدِيْقًابِكِتَابِكَوَوَفَاءًبِعَهْدِكَوَإِتِّبَاعًالِسُنَّةِنَبِيِّكَمُحَمَّدٍصَلَّياللّٰهُعَلَيْهِوَسَلَّمَ.», and then begin the tawaf.