If a traveler leads a group of travelers in prayer and completes the prayer without shortening it, are they obligated to follow him, or do they shorten it?

The Shaykh : Yes, Ya 'A'id.

The questioner : The questioner says: If a traveler prays with a traveler, and the imam completes the prayer, what is required of the follower? Is he obligated to complete it or shorten it?

The Shaykh : How?

The questioner : If a traveler prays with a traveler.

The Shaykh : Yes, that is correct.

The questioner : And the imam completes the prayer, is it obligatory for the follower to complete it or shorten it?

The Shaykh : Meaning, the imam is a traveler and he completed the prayer?

The questioner : Yes, that is correct.

The Shaykh : The follower is obligated to complete the prayer following his imam. That is, if a traveler prays behind an imam who completes the prayer, he is obligated to complete it, whether this imam is a traveler or a resident. This is due to the generality of the saying of the Prophet (peace and blessings be upon him): .
And his saying: "And Ibn 'Abbas (may Allah be pleased with him and his father) was asked: What about a traveling man who prays two rak'ahs, while with the imam he prays four? He said: That is the Sunnah."