The following incident sheds light on the deep love that Hazrat ‘Ali (radhiyallahu ‘anhu) had for Hazrat ‘Umar (radhiyallahu ‘anhu). Hazrat ‘Ali (radhiyallahu ‘anhu) loved Hazrat ‘Umar (radhiyallahu ‘anhu) to such an extent that he changed his intention of marrying his daughter to his nephew and instead married her to Hazrat ‘Umar (radhiyallahu ‘anhu).
Hazrat ‘Umar (radhiyallahu ‘anhu) once proposed to the daughter of Hazrat ‘Ali and Hazrat Faatimah (radhiyallahu ‘anhuma), Hazrat Ummu Kulthoom. On receiving the proposal, Hazrat ‘Ali (radhiyallahu ‘anhu) initially excused himself, explaining that he had reserved his daughters for the marriage of the sons of his brother, Hazrat Ja‘far (radhiyallahu ‘anhu). Hazrat ‘Umar (radhiyallahu ‘anhu) again requested him saying, “Marry her to me! By the oath of Allah, there is no person on the surface of the earth who will appreciate her nobility as I will.” Hearing this, Hazrat ‘Ali (radhiyallahu ‘anhu) agreed and married her to Hazrat ‘Umar (radhiyallahu ‘anhu).
Hazrat ‘Umar (radhiyallahu ‘anhu) thereafter went to the Muhaajireen (radhiyallahu ‘anhum) and exclaimed in joy, “Congratulate me over my nikaah!” They all congratulated him and enquired as to whom he had married. He replied, “The daughter of Hazrat ‘Ali (radhiyallahu ‘anhu).” He then explained, “Verily Rasulullah (sallallahu ‘alaihi wasallam) said, ‘Every relationship between people will be severed on the day of Qiyaamah besides the relationship which people had with me or because of me (besides the relationship which people had with me through family ties and besides the relationship they had with me through following my example in piety and taqwa).’ I had married my daughter to Nabi (sallallahu ‘alaihi wasallam) and so I also wished to marry a descendant of the Ahl-e-Bayt, the family of Rasulullah (sallallahu ‘alaihi wasallam).” (Isaabah 8/465, Radd-ul-Muhtaar 2/198)
Note: Hazrat Umar (radhiyallahu ‘anhu) wished to acquire the special relationship of Rasulullah (sallallahu ‘alaihi wasallam) through being part of his mubaarak family, just as he had acquired the relationship of Rasulullah (sallallahu ‘alaihi wasallam) through following his mubaarak example in piety and taqwa.