It was narrated that Suhaib, the Companion of the Messenger of Allah صلی اللہ علیہ وآلہ وسلم said: “I passed by the Messenger of Allah صلی اللہ علیہ وآلہ وسلم when he was praying, and greeted him with Salam. He returned my greeting with a gesture, or maybe it was just with his finger.”(Sahih).