He is given the choice between performing it or abandoning it, like all other concessions. Ya‘la ibn Umayyah said: I said to ‘Umar ibn al-Khattab: "'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,'" to which he replied: "I wondered about the same thing that you wondered about, so I asked the Messenger of God, peace and blessings of God be upon him, and he said: 'It is a charity that God has bestowed upon you, so accept His charity.'" Recorded by Muslim. This indicates that it is a concession and not a strict obligation (azimah), and that it is shortened. Al-Aswad narrated from ‘A’ishah that she said: "I went out with the Messenger of God, peace and blessings of God be upon him, on the ‘Umrah of Ramadan, so he broke his fast and I fasted, and he shortened [his prayer] and I completed [it], so I said: 'O Messenger of God, may my father and mother be sacrificed for you, you broke your fast and I fasted, and you shortened [your prayer] and I completed [it].' He said: 'You have done well.'" Recorded by Abu Dawud al-Tayalisi in his Musnad. This is explicit regarding the ruling. Furthermore, if he were to follow an Imam who is a resident, he would pray four [rak‘ahs], and the prayer would be valid, and prayer does not increase by following an Imam. Ibn ‘Abd al-Barr stated: "The consensus of the majority of jurists that when a traveler joins the prayer of residents and catches one rak‘ah, he is bound by four, is clear evidence that shortening is a concession. For if his mandatory prayer were [only] two rak‘ahs, he would not be bound by four under any circumstances." He also narrated with his chain of transmission from ‘Ata’ from ‘A’ishah: "The Messenger of God, peace and blessings of God be upon him, would complete the prayer in travel and would shorten it." And from Anas, who said: "We, the companions of the Messenger of God, peace and blessings of God be upon him, used to travel; some of us would complete the prayer and some would shorten it, and some of us would fast and some would break our fast, and no one would blame another."