Doesn't the woman need her guardian's approval to marry?

In the name of Allah, Most Compassionate, Most Merciful, It is certainly the sunna and proper way to get one’s guardian’s permission. The danger of going against one’s parents (in normal cases) is that it could well entail ‘being bad’ to one’s parents, which is one of the most serious of major sins. According to the understanding of the Hanafi Madhhab, if a mature woman contracted her marriage without the approval of her guardian to someone who is considered legally suitable (kuf'u), then the marriage is valid. However, if she is marrying someone that is not considered legally suitable or compatible, then this will need the approval of the father (or, in his absence, the nearest fit guardian).

The relied-upon opinion is that in the absence of this approval from the guardian, a woman's marriage to a non-suitable man is not valid. If they live together, they are living together unlawfully. As such, if such situations come up, both parties must consult a scholar of recognized knowledge and taqwa for guidance, and to determine what their status is.

This has also been explained in many earlier posts.

And Allah knows best

Muhammad ibn Adam al-Kawthari
Darul Iftaa, Leicester, UK

[Source: SunniPath]