Sunan An-Nasa'i

It was narrated that Jabir said:""The Messenger of Allah (ﷺ) sent me on an errand, then I came back to him while he was facing the east or the west. I greeted him with salam and he gestured to me. Then when he finished he called me and said: ""O Jabir!"" So I came and said: ""O Messenger of Allah, I greeted you with Salam but you did not answer."" He said: 'I was praying