What should a girl do if she believes the niqab is obligatory, but her parents refuse and threaten to prevent her from wearing the الشرعي hijab as well if she wears the niqab? And what do you say to those who argue with the common saying, "the face and the hands"? And is it permissible to wear the niqab in certain places and remove it in others if she believes it is obligatory?

Obedience to parents is obligatory in what is permissible, but it is not permissible to obey them if they command something that contradicts Islamic law. As long as you believe in the obligation of wearing the niqab, it is not permissible for you to obey your parents in removing it. However, you must honor them, be kind to them, and obey them in what is permissible. If they do not agree, they have no right to prevent you from wearing the niqab. If opposing them is difficult for you, then you should not leave the house except for a necessity or a dire need. You can wear the niqab without their knowledge. There is no blame upon you if you remove it when you are unable to wear it and wear it when you are able, for what is easy does not negate what is difficult. Their right over you is great, and honoring them is one of the greatest acts of drawing closer to Allah, so beware of mistreating them or speaking harshly.