Is it permissible to prevent a Muslim girl from marrying a Muslim man due to differences in nationality or tribe, even if all the Shariah conditions are met?

Compatibility in marriage is considered, by scholarly consensus, especially concerning religious commitment. Thus, an immoral person is not compatible with a chaste woman. This is supported by the Prophet's (peace be upon him) saying: "If someone whose religious commitment and character you approve comes to you seeking marriage, then marry him. If you do not do so, there will be tribulation on earth and widespread corruption."

As for compatibility in lineage, scholars have differed on this. Some have considered it, because Arabs value compatibility in lineage and disdain marrying freed slaves (mawali). Others have not considered it, citing Allah's saying: (Indeed, the most noble of you in the sight of Allah is the most righteous of you), and the Prophet's (peace be upon him) saying: "There is no superiority for an Arab over a non-Arab, nor for a non-Arab over an Arab, nor for a white person over a black person, except by piety."

The preponderant opinion is that the only compatibility that matters is religious commitment. A Muslim man of approved religious commitment and character can marry any Muslim woman, regardless of her lineage, country, or tribe.

The guardian (wali) is a condition for marriage. If the guardian prevents a woman from marrying someone who meets the conditions, the woman has the right to take her case to the Sharia courts.