Why does the Quran discourage the asking of questions?
This is in reference to those who asked useless questions about revelation. If all their questions were answered, it would have made the duties of faith more specific and, therefore, more difficult to perform. There is mercy in leaving questions alone and specifics unspecified. 7
In Chapter 2 of the Quran, when the Children of Israel were told to slaughter a cow, they began to ask useless questions about what type of cow. All the questions were answered to the point that it became very difficult for them to find such a cow. If they had not asked, any cow would have been acceptable.
Useless, petty questions are just a stalling tactic; ask any mother or teacher. But asking honest, sincere questions to clarify matters of faith is, in fact, encouraged.