Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with him), he says that the Messenger of Allah (peace and blessings be upon him) asked Sayyiduna Abu Bakr (may Allah be pleased with him): "At what time do you perform the Witr prayer?" He said: "After 'Isha, in the first part of the night." Then the Prophet (peace and blessings be upon him) asked (Sayyiduna Umar, may Allah be pleased with him): "And Umar, when do you (perform it)?" He said: "In the last part of the night." Then the Noble Prophet (peace and blessings be upon him) said: "Abu Bakr, you have chosen a cautious practice, and Umar, you have adopted a strong (i.e., difficult) practice."