Umme Kulthum (R.A) was Rasulullah’s (Sallallahu Alaihi Wasallam) third daughter. She too, was married like her sister to the son of Abu Lahab, Utaiba. Utaiba too like his brother, divorced Umme Khulthum (R.A).
When her elder sister Ruqayyah (R.A) passed away, Umme Kulthum was given in marriage to Uthman (R.A.).
A narratable situation had arisen on that occasion.
Hafsa (R.A) the daughter of Umar (R.A) had become a widow when she was only 18 years old. Umar (R.A) offered Uthman (R.A) to take her in marriage who was very disconsolate after the death of Ruqayyah but he refused. Umar (R.A) was hurt by his refusal.
He then went to Abu Bakr (R.A) whom he counted as his best friend and made to him the same offer. His evasive answer disappointed him even more.
Umar (R.A) went to Rasulullah (Sallallahu Alaihi Wasallam) and gave vent to his grievance. Rasulullah (Sallallahu Alaihi Wasallam) said to him, “Behold! I will show you a better son-in-law than Uthman, and I will show him a better father-in-law than you.” “So be it.” said Sayyidinah Umar (R.A) with a glee on his face.
Umar (R.A) in a moment’s reflection found that the better man referred to was none other than Rasulullah (Sallallahu Alaihi Wasallam) who would himself take Hafsa (R.A) in his marriage and who would become, for the second time the father-in-law of Uthman (R.A) by giving him in marriage Ruqayyah’s (R.A) sister Umme Kulthum (R.A).
Source : eislam