Daily Hadith Wed 25-Nov-2009 - 07 Dhul-Hijjah 1430 حديث اليوم
Undesirability of Quarrelling or Raising voices in the Mosque
As-Sa`ib bin Yazid (May Allah be pleased with him) said: While I was in the mosque, someone threw a pebble at me, and when I looked up, I saw that it was `Umar bin Al-Khattab, who said: "Go and call me these two men." I brought them and `Umar (May Allah be pleased with him) asked them: "Where are you from?" On their replying that they belonged to At-Taif, he said: "Had you been the inhabitants of Al-Madinah, I would have given you a beating for raising your voices in the mosque of the Messenger of Allah (PBUH)."[Al-Bukhari].


Commentary:
The action of `Umar (May Allah be pleased with him) mentioned in the Hadith tells us that to speak loudly in the mosque amounts to desecrating it, which is a punishable offense.
2. If one is able of it, he must stop people from acts which amount to denial of Divine injunctions and contravene the Shari`ah.

310/1700 - Riyad Us-Saliheen (Gardens of the Righteous)
باب كراهة الخصومة في المسجد
ورفع الصوت فيه ، ونشد الضالة والبيع والشراء والإِجارة ونحوها من المعاملات
وَعَنِ السَّائِبِ بْنِ يزيدَ الصَّحَابي رَضِيَ اللَّه عنْهُ قالَ : كُنْتُ في المَسْجِدِ فَحَصَبني رَجُلٌ ، فَنَظَرْتُ فَإِذَا عُمَرُ بنُ الخَطَّابِ رَضِيَ اللَّه عَنْهُ فَقَالَ : اذهَبْ فأْتِني بِهَذيْنِ فَجِئْتُهُ بِهمَا، فَقَالَ : مِنْ أَيْنَ أَنْتُمَا ؟ فَقَالا : مِنْ أَهْلِ الطَّائِفِ ، فَقَالَ : لَوْ كُنْتُمَا مِنْ أَهْلِ الْبَلَدِ ، لأَوْجَعْتُكُمَا ، تَرْفَعَانِ أَصْوَاتَكُمَا فِي مسْجِدِ رَسُولِ اللَّهِ صَلّى اللهُ عَلَيْهِ وسَلَّم ؟ رَوَاهُ البُخَارِي .
1700/310 - رياض الصالحين
Wed 25-Nov-2009 - 07 Dhul-Hijjah 1430