The Messenger of Allah ﷺ sent me on an errand, and then I caught up with him while he was traveling. (Qutayba said, "while he was praying.") I greeted him with salaam, and he gestured to me. When he finished, he called me over and said, "You greeted me just now while I was praying," and at that time he was facing toward the east.
إن رسول الله ﷺ بعثني الحاجة ثم أدركته وهو يسير (قال قتيبة: يصلي) فسلمت عليه. فأشار إلي. فلما فرغ دعاني فقال: إنك سلمت آنفا وأنا أصلي وهو موجه حينئذ قبل الشرق.
Muslim narrated it in "The Mosques" (540) from Qutayba bin Saeed, who said, Layth bin Saad related to us, from Abu Zubayr, from Jabir, who mentioned something similar. He also narrated it from Ahmad bin Yunus, who said, Zuhayr related to us, saying, Abu Zubayr told me, from Jabir, and in it, "He was praying on his camel, so I spoke to him. He gestured to me with his hand like this" (Zuhayr gestured with his hand), "then I spoke to him and he gestured to me like this" (Zuhayr again gestured with his hand toward the ground).Ibn Khuzayma narrated it (889) through the route of Khallad Jufi, meaning Ibn Yazid, from Zuhayr, with the same account, and in it, "He was on a donkey of his, praying. I would speak to him, and he would gesture to me with his hand."Nasai narrated it (1191) through another route from Amr bin Harith, who said, Abu Zubayr told me, with the same account, and in it, "So I greeted him, and he gestured with his hand. Then I greeted him again, and he gestured with his hand, so I left. Then he called out to me, 'O Jabir,' and the people called out to me, 'O Jabir!' So I went to him and said, 'O Messenger of Allah, I greeted you but you did not return my greeting.' He said, 'I was praying.'"