Are children sinful for feeling distressed and saddened by their father's refusal to give them a monthly allowance? And is criticizing the father for his stinginess towards them and his lack of consideration for them considered a rebellion against Islamic law or an act of disbelief, especially since society is accustomed to the father spending on his children in all their affairs, including monthly allowances and university education?

There is no sin in children feeling distressed and sad about being denied an allowance beyond their needs, unless it is accompanied by something forbidden, such as disobedience to parents or discontent with Allah's Shari'a. Criticizing the personal behavior of someone who withheld the customary excess allowance does not necessitate discontent with the Shari'a, unless the motive is inner discontent and objection to a matter of Shari'a. This would then fall under the disbelief of abhorrence and hatred for something from Allah's religion. Whoever hates anything that the Messenger of Allah, peace and blessings be upon him, brought has disbelieved, due to Allah's saying: {That is because they hated what Allah revealed, so He rendered their deeds worthless}.