God made it obligatory upon him.

271 - Issue: He said: "The traveler is permitted to complete [the prayer] and to shorten it, just as he is permitted to fast or break his fast."

The famous position from Ahmad is that if the traveler wishes, he prays two rak‘ahs, and if he wishes, he completes it. It is also narrated that he [Ahmad] hesitated, saying: "I prefer safety from this issue." Among those who were narrated to have permitted completing the prayer while traveling are Uthman, Sa‘d ibn Abi Waqqas, Ibn Mas‘ud, Ibn ‘Umar, and ‘A’ishah, may God be pleased with them. This is the opinion of al-Awza‘i, al-Shafi‘i, and it is the famous position from Malik. Hammad ibn Abi Sulayman said: "He is not permitted to complete the prayer while traveling," which is the position of al-Thawri and Abu Hanifah. Hammad deemed it obligatory for the one who completes the prayer to repeat it. The proponents of opinion [Ashab al-Ra’y] said: "If he sat after the two rak‘ahs for the duration of the tashahhud, his prayer is valid; otherwise, it is not valid." ‘Umar ibn ‘Abd al-‘Aziz said: "Prayer in travel is two rak‘ahs definitively; nothing else is acceptable." It is narrated from Ibn ‘Abbas that he said: "Whoever prays four in travel is like one who prays two in residency." They argued that prayer in travel is two rak‘ahs based on the statement of ‘Umar, ‘A’ishah, and Ibn ‘Abbas, as we have mentioned. It is narrated from Safwan ibn Muhriz that he asked Ibn ‘Umar about prayer in travel, and he replied: "Two rak‘ahs; whoever opposes the Sunnah has disbelieved." And because the two additional rak‘ahs are permitted to be left out without a replacement, it is not permitted to increase them upon the two obligatory rak‘ahs, just as one would not add them to the dawn prayer. As for us, we rely on the word of God, the Almighty: "And when you travel throughout the land, there is no blame upon you for shortening the prayer, [especially] if you fear that those who disbelieve may disrupt [or attack] you," and this indicates that shortening is a concession.