This thread is ridiculious.It has been clearly stated in the Quran by the Almighty.Title seems to be questioning the credibility of the Quran.You should have asked "How namaz prevents from committing Sin ?" We are not suppose to ask " Is hajj obligatory for a Muslim? " or "should Muslims fast" or "Is there really only one God". these all are established facts because Allah has said that.Similarly there should be no doubt in mind that Namz prevents from commiting sin because it has been clearly stated by Allah in the Quran.

How namaz prevent from commiting sins is another issue and we can debate on that.Namaz does prevent,there should be no doubt about it.

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