The Messenger of Allah (Sallallaahu 'alaihi wasallam) said,
"Everyone among you will be deemed to be occupied in Salat (prayer) constantly so long as Salat (the prayer) detains him (from worldly concerns), and nothing prevents him from returning to his family but Salat.''
[Al-Bukhari and Muslim]
Commentary:
This Hadith tells us the merits of waiting for Salat. As long as a person sits in mosque waiting for Salat, all his time is reckoned as being in the state of Salat and so eligible for the same reward.