Then sit and wait for the prayer. While you are seated in the mosque awaiting the prayer, keep yourself busy with the remembrance of Allah and the recitation of the Quran. Avoid aimless actions—such as interlacing your fingers and the like—for a specific prohibition has been reported for the one who is waiting for the prayer. The Prophet said, “If any of you is in the mosque, let him not intertwine his fingers, for intertwining is from Satan.”
If someone is in the mosque for a purpose other than waiting for the prayer, however, he is not forbidden to interlace his fingers, for it is authentically reported that the Prophet himself interlaced his fingers in the mosque after concluding the prayer.
While you are waiting for the prayer in the mosque, do not plunge into worldly conversations. A hadith states that such talk consumes good deeds just as fire consumes firewood. In another hadith it is said that a servant remains in a state of prayer so long as he is waiting for the prayer, and the angels keep seeking forgiveness for him. So, O Muslim, do not squander this reward by wasting the time in frivolity and idle chatter.