Meaning: O Allah, open for me the gates of Your mercy.
*One should exit the masjid with his left foot, and say: 'Al'laahum'ma sal'lee wa sal'lim ala Muhammad wa ala aa'lee Muhammad al'laahum'ma in'nee as'a'lo'ka min fad'le'ka.'17
Meaning: O Allah, I ask You from Your bounties. *One should perform Tahiyatul Masjid upon entering the Masjid, as is mentioned in the hadeeth of Abu Qatadah () as-Sulami, that the Messenger of Allah () said:
'If one of you enters the Masjid, let him perform a two unit prayer before he sits down.'(Bukhari) One should perform Tahiytaul Masjid upon entering the Masjid, even if he enters it during a time of prohibition.
*There is great reward for sitting in the Masjid and waiting for the prayer. The Prophet () said:
'When one enters the Masjid he will be as though he is in prayer as long as the person is waiting to perform the next prayer. The angels will supplicate Allah for him as long as he is in this position; they will supplicate, saying: 'Al'laahum'ma ir'ham'who (O Allah have mercy on him) Al'laahum'ma ighfir'la'who, Al'laahum'ma tob a'laih' (O Allah forgive him) as long as he does not break hiswudhu.' (Bukhari) *It is inappropriate for one to sit with people in the Masjid who talk about worldly affairs; the Prophet () prophesized that this would happen. He () said:
'A time will come when people sit in the Masjid and only discuss worldly affairs. Allah does not need them, so do not sit with them.'(Hakim) *It is appropriate that one not use the Masjid to talk falsehood or idle talk. One should not raise their voice to say something blameworthy.
*It is lawful for one to lie down in the Masjid. Abdullah b. Zaid () said that he saw the Messenger of Allah () lying down on his back in the Masjid and he had outstretched his feet placing one atop the other.
*It is lawful for one to stretch their feet towards the Qiblah. One should avoid stretching their feet towards the Mushaf (i.e. the Qur'an) out of respect for the words of Allah.
*It is lawful for one to sleep in the Masjid for the people of as-Suffah would sleep in the Masjid. If one has a wet-dream while in the Masjid, he should quickly rush out of the Masjid and perform Ghusl. Ibn Umar () who was an unmarried youth at that time would sleep in the masjid of the Messenger of Allah ().
*It is unlawful for one to conduct sales in the Masjid. The Prophet () said:
'If you see someone selling in the Masjid say to them: 'May Allah not give success to you in your sales.'(Hakim) *It is inappropriate for one to place advertisements for products in the Masjid.
*It is inappropriate for one to call out and ask people in the Masjid if they found something that he lost. If this happens it should be said to him:
'May Allah not return your lost item to you for the Masjid is not built for this purpose.'(Muslim) *It is lawful for one to raise his voice in the Masjid to spread knowledge and when ordering with good things; one should not raise his voice in the Masjid for any other purpose.
*One should not intertwine his fingers when sitting in the Masjid and waiting for a prayer. Ka'b b. A’jurah () said that the Messenger of Allah () said:
