What is the ruling on a marriage concluded without the knowledge of the girl's legal guardian, and is it considered invalid based on the Messenger of Allah (peace and blessings be upon him) saying: "Any woman who marries without the permission of her guardian, her marriage is invalid"? And is this considered an act of disobedience by the girl to her family?

If a father rejects a suitor due to his bad character, he is not being unjust to his daughter. The marriage of a girl without her guardian's consent is invalid according to the majority of scholars, and her action in doing so is considered disobedience to her parents due to the severe harm it causes them. It should be noted that the maternal uncle has no guardianship in marriage; rather, the guardian is the father, then the paternal grandfather, then the son, then the full brother, then the paternal half-brother, then their sons, then the paternal uncles.