Sahih Muslim Book 18, Hadith Number 4259.

Chapter : It is forbidden to ask many questions, and wasting of wealth.

Sha’bi reported that the scribe of al-Mughira b. Shu’ba said: Mu’awiya wrote to Mughira: Write for me something which you heard from Allah’s Messenger (may peace be upon him); and he wrote: I heard Allah’s Messenger (may peace be upon him) as saying. Verily Allah disapproves three thingq for you: irrelevant talk, wasting of wealth and persistent questioning.