What is the ruling on and the consequences of marriage without the parents' approval?

The pleasure of one's parents is among the greatest acts of proximity to Allah, for in it lies the pleasure of Allah Almighty. A child should strive to earn the pleasure of their parents in marriage and other matters. Obedience to them takes precedence in refraining from marrying someone they do not approve of, and this is obligatory unless there is another overriding benefit. Disobeying parents in this situation is considered an act of disobedience (uquq), which is a grave sin that may lead to dire consequences and lack of blessing in the marriage, as Allah Almighty says: "And whatever strikes you of disaster - it is because of what your hands have earned, and He pardons much."