Mishkat al-Masabih 4 Prayer كتاب الصلاة 197

وَعَنْ عَمْرِو بْنِ شُعَيْبٍ عَنْ أَبِيهِ عَنْ جَدِّهِ قَالَ: رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُصَلِّي حافيا ومتنعلا. رَوَاهُ أَبُو دَاوُد

‘Amr b. Shu’aib, on his father’s authority, said that his grandfather declared he had seen God’s Messenger praying both barefoot and wearing sandals. Abu Dawud transmitted it.