A couple wants to get married. The boy's parents have consented, but the girl's parents refuse.

Answer

If the girl is a follower of the Shaafi' Math-hab, the Nikah without her father's consent will not be valid. If she is a Hanafi, then while the Nikah will be valid without the father's consent, nevertheless, it will be sinful for her to marry in conflict with the wishes of her parents. Such marriages are usually devoid of barkat and happiness. If the parents have a valid reason for refusing permission, the boy should not insist. He should terminate immediately the relationship and not conduct a clandestine affair in which he incurs the Wrath of Allah Ta'ala. No matter how difficult it may be, the boy and the girl should muster up courage and not get married against the wishes of their parents.

We have seen many such marriages ending up on the rocks. Soon after the marriage, problems develop. What happiness will the girl have if her parents who had reared and nourished her for all these years are unhappy?

The one issue is the displeasure of the parents which is a very serious matter. The other issue is Allah's displeasure. It will be extremely unintelligent and ridiculous if the girl to please her parents does not proceed with the marriage, but continues to maintain a relationship with the boy. Such a relationship in Islam is called zina. It will be a greater sin to continue having contact with the boy. If they are determined to continue the haraam relationship, then it will be better to get married even without the consent of the parents. But then they must be prepared for unhappiness after marriage. But if the girl is a Shaafi', a male Wali is imperative for the validity of the marriage.