On account of his enmity for Rasulullah (sallallahu ‘alaihi wasallam), Abu Lahab made his two sons, ‘Utbah and ‘Utaibah, divorce the two respected daughters of Rasulullah (sallallahu ‘alaihi wasallam), Hazrat Ruqayyah (radhiyallahu ‘anha) and Hazrat Ummu Kulthoom (radhiyallahu ‘anha), whom they had married before the prophethood of Rasulullah (sallallahu ‘alaihi wasallam). The reason for Abu Lahab doing this was to cause pain to the blessed heart of Rasulullah (sallallahu ‘alaihi wasallam). However, in reality, this divorce was a source of Allah Ta‘ala’s mercy. One after the other, both these daughters were eventually married to Hazrat ‘Uthmaan (radhiyallahu ‘anhu), due to which he was honored with the title ‘Zun-Noorain’ (the possessor of the two lights). From all the companions of the one hundred and twenty four thousand Ambiyaa (‘alaihimus salaam), only Hazrat ‘Uthmaan (radhiyallahu ‘anhu) had the honor of getting married to two daughters of a Nabi, thereby earning the title Zun-Noorain.

(Extracted from Seeratul Musatafa 1/174)