Abu Ubayd (may Allah have mercy on him) said: According to many people, al-mawla means specifically the paternal cousin, but it is not so; rather it means the guardian (wali). Every guardian of a person is his mawla, such as the father, the brother, the brother's son, the paternal uncle, the paternal uncle's son, and all the agnatic relatives ('asabah) beyond them. From this is the saying of Allah Almighty: "And indeed, I fear the heirs (mawali) after me." [Surah Maryam: 5] He said: Among what makes it clear to you that al-mawla is every guardian is the hadith of the Prophet (peace and blessings be upon him): "Any woman who marries without the permission of her mawla, her marriage is void"; by mawla he (peace and blessings be upon him) meant the guardian. And Allah Almighty said: "The Day when a mawla will not avail a mawla in anything." [Surah al-Dukhan: 41] Do you think that only the paternal cousin is meant by it, to the exclusion of the rest of his household?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13600