When ‘Abdul Muttalib finally completed paying the ransom for ‘Abdullah’s life, his next concern was to get him married. He sent a marriage proposal on behalf of ‘Abdullah for the hand of Aaminah, the daughter of Wahb bin ‘Abdu Manaaf of the eminently noble Banu Zuhrah tribe. She was, at that time, under the guardianship of her uncle, Wuhaib bin ‘Abdu Manaaf.
‘Abdul Muttalib also sent a marriage proposal for himself, asking for the hand of Haalah, the daughter of Wuhaib bin ‘Abdu Manaaf, Aaminah’s uncle. Both proposals were accepted and both father and son were married in the same session. Hazrat Hamzah (radhiyallahu ‘anhu), the son of ‘Abdul Muttalib, was born from her (Haalah). Hazrat Hamzah (radhiyallahu ‘anhu) was Rasulullah’s (sallallahu ‘alaihi wasallam) paternal uncle as well as his milk-brother.
(Extracted from Seeratul Mustafa 1/44)