Sahih al-Bukhari Book 77, Hadith 183
While I was riding behind the Prophet (ﷺ) and between me and him and between me and him there was
only the back of the saddle, he said, "0 Mu`adh!" I replied, "Labbaik, 0 Allah's Messenger (ﷺ), and Sa`daik!"
he said, "Do you know what is Allah's right upon his slave?" I said, "Allah and His Apostle know
best" He said "Allah's right upon his slaves is that they should worship Him alone and not worship
anything else besides Him." Then he proceeded for a while and then said, "O Mu`adh bin Jabal!" I
replied, "Labbaik, O Allah's Messenger (ﷺ):, Sa`daik!' He said, "Do you know what is the right of the
slaves upon Allah if they do that?" I replied, "Allah and His Apostle know best." He said, "The right
of the slaves upon Allah is that He will not punish them (if they do that).
The worst of three (persons riding one, animal) was mentioned in `Ikrima's presence `Ikrima said, "Ibn `Abbas said, '(In the year of the conquest of Mecca) the Prophet (ﷺ) came and mounted Qutham in front of him and Al-Fadl behind him, or Qutham behind him and Al-Fadl in front of him.' Now which of them was the worst off and which was the best?"
We were coming from Khaibar along with Allah's Messenger (ﷺ) while l was riding behind Abu Talha and he was proceeding. While one of the wives of Allah's Messenger (ﷺ) was riding behind Allah's Messenger (ﷺ), suddenly the foot of the camel Slipped and I said, "The woman!" and alighted (hurriedly). Allah's Apostle said, "She is your mother." Sol resaddled the she-camel and Allah's Messenger (ﷺ) mounted it. When he approached or saw Medina, he said, "Ayibun, ta'ibun, 'abidun, li-Rabbina hami-dun."