Ibn Hazm:

“We have also transmitted it through Hudhayfah, Jābir, Zayd ibn Thābit, Abū Hurayrah and Ibn ʿUmar from the Prophet, peace and blessings be upon him, with chains of transmission of the highest authenticity.”

Ibn Hazm said:

“On the basis of this verse, we hold that a person offering the prayer of fear while travelling may pray one rakʿah or two, as he wishes. This is because the Quran uses the wording ‘There is no blame,’ rather than a command imposing an obligation. The people prayed it with the Prophet, peace and blessings be upon him, sometimes as just one rakʿah and sometimes as two. It was therefore a matter of choice, as Jābir said.”

As for ʿUthmān’s prayer, the leading Companions’ disapproval of his practice is well known. Nevertheless, they would pray behind him. Indeed, Ibn Masʿūd would pray four rakʿahs even when praying alone, saying, “Discord is evil.” Ibn ʿUmar, however, would pray two rakʿahs when praying alone.

This shows that they regarded praying four rakʿahs while travelling as disliked and contrary to the Sunnah. Nevertheless, anyone who does so need not repeat the prayer, and if the imam does so, he is to be followed. This is because the traveller’s prayer is not like the Fajr prayer; rather, it belongs to the same category as the Friday prayer and the two Eid prayers. Hence, in the Sunnah he transmitted, ʿUmar ibn al-Khattāb grouped these four together, saying:

“The Eid al-Adhā prayer is two rakʿahs, the Eid al-Fitr prayer is two rakʿahs, the Friday prayer is two rakʿahs, and the traveller’s prayer is two rakʿahs—complete, not shortened, as declared by your Prophet. Whoever fabricates lies has indeed failed.”

Ahmad and al-Nasāʾī narrated this through ʿAbd al-Rahmān ibn Abī Laylā, from Kaʿb ibn ʿUjrah, who said: “ʿUmar said…” It was also narrated by Yazīd ibn Ziyād