Chapter: It is recommended to greet the masjid by praying two rak`ah, and it is disliked to sit before praying these two rak`ah, and this is prescribed at all times
Jabir b. 'Abdullah reported: I went with the Messenger of Allah ( صلی اللہ علیہ وسلم ) on an expedition and my camel delayed me and I was exhausted. The Messenger of Allah ( صلی اللہ علیہ وسلم ) thus came earlier than I, whereas I came on the next day and went to the mosque and found him (the Holy Prophet) at the gate of the mosque. He said: It is now that you have come. I said. Yes. He said: Leave your camel and enter (the mosque) and observe two rak'ahs. He (the narrator) said: So I entered and observed (two rak'ahs) of prayer and then went back.
Authentic