on the authority of abu tha'labah al-kushanee - jurthoom bin naashir (radiallaahu anhu) - that the messenger of allaah (sallallaahu alayhi wa sallam) said :

a hasan hadeeth narrated by ad-daaraqutnee and others.

explanation of hadeeth number 30

his (sallallaahu alayhi wa sallam) statement "has laid down" means that allaah 'azza wa jall has made these things obligatory. and his statement "so do not overstep them" means do not enter into them. and as for the forbiddance from delving into those matters which allaah has remained silent about, then it is in accordance with his (sallallaahu alayhi wa sallam) statement : "do not ask me about that which i have left [unspecified], for the earlier nations were destroyed because of their excessive questioning and their disagreeing with their prophets" [see hadeeth number 9]. some of the 'ulamaa have said : "the banoo israa'eel used to ask [much] and they were answered and given what they asked for, until this became a fitnah (trial) for them, and this brought them towards their destruction."

and the sahaabah (radiallaahu 'anhum) understood this, and restrained from asking except in those matters which were essential. [due to this] they would be delighted when a desert bedouin [who would not be so restrained] would come to ask the messenger of allaah (sallallaahu alayhi wa sallam) questions, so they would listen attentively.

and some people became extreme in this until they said : "it is not permssible to ask the scholars about new events/situations until they actually occur." and the salaf [ie the early scholars] used to say similar to this, that is to leave such matters until they actually occurred. [this continued] until they began to fear that knowledge would be lost [through the death of the 'ulamaa], and so they began to lay down principles, and discuss finer issues, and to arrange and write down the different branches of knowledge and their rulings.

and the 'ulamaa have differed regarding the ruling on matters before the sharee'ah was revealed about them [ie during the life of the prophet sallallaahu alayhi wa sallam] - were they all forbidden or permissible or was there no ruling about them at all ? so the 'ulamaa have split into three madhhabs on this issue, and all this is mentioned in detail in the books of usool ul-fiqh.

summary :

• that a muslim has specified enjoined duties to perform in his religion, which he cannot neglect
• that allaah has shown us how and where not commit excesses
• that he has set limits and prohibitions, which also cannot be neglected
• that what is known clearly from the book and the sunnah is enough for our lives, and this is a mercy from allaah
• that we should not seek after what has not been mentioned
• that speculating, philosophising and hypothesising about islaam is forbidden
• that allaah never forgets