Sayyiduna Ibn Umar (may Allah be pleased with them both) narrated from Sayyiduna Suhaib (may Allah be pleased with him) that he (Suhaib) passed by the Messenger of Allah (peace and blessings be upon him) and greeted him with salam while the Prophet (peace and blessings be upon him) was praying. The Prophet (peace and blessings be upon him) replied to the salam with a gesture. The narrator of the hadith, Layth, said: I think he said that he replied to the salam with a gesture of his finger.

Narrated by Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) came to the mosque of Banu Awf bin Amr (which is in Quba), and he began to pray, and the people filled the mosque. They would greet him with salam, and Sayyiduna Ibn Umar (may Allah be pleased with them both) said: I asked (Sayyiduna) Suhaib (may Allah be pleased with him): How did the Noble Prophet (peace and blessings be upon him) reply to salam (while in prayer)? He indicated with his hand: He would reply in this manner.