What is the Sunnah that is obligatory for the traveler?

The Shaykh : The questioner asks: What is the Sunnah that is obligatory for the traveler? The word "obligatory" combined with his phrase "what is the Sunnah" creates a problem for me, because if he means by "Sunnah" the customary meaning in the time of the Messenger (peace and blessings be upon him), which includes the obligatory and the recommended, then there is an answer to that. And if he means by "Sunnah" the voluntary acts, which is the terminology of the scholars, especially the later ones, then there is an answer to that as well. If he means the first, the comprehensive Sunnah that includes the obligatory and the recommended, then the Sunnah for the traveler regarding prayer is to shorten it if it is a four-rak'ah prayer. So he prays Dhuhr, 'Asr, and 'Isha' in two rak'ahs, two rak'ahs, unless he prays behind an imam who completes the prayer, in which case it is obligatory for him to complete it, whether he catches the imam at the beginning of the prayer or catches him in the middle of the prayer. This is due to the generality of the saying of the Prophet (peace and blessings be upon him) , and because Ibn 'Abbas (may Allah be pleased with him and his father) was asked about a man who is with the imam and prays four rak'ahs, so he said: "That is the Sunnah." Based on this, we say that the Sunnah for the traveler regarding shortening is to pray the four-rak'ah prayer in two rak'ahs. As for combining prayers, the Sunnah is not to combine unless there is a need to be relieved by doing so. That is, if he needs to combine, such as if he is traveling on the road and wants to stop only once, he combines the first prayer with the second. Or if he is staying and will walk, and wants to combine the second with the first, then it is from the Sunnah to combine if that is more comfortable for him. But if there is no comfort in it for him, and the matter is the same for him, then if he wishes he combines, and if he wishes he does not combine, and not combining is better. However, if the traveler is in a town and is one of the people of the congregation, then it is obligatory for him to attend the congregation. So he prays in the mosque with the Muslims, completing the prayer, and he does not combine unless he intends to travel after he prays. In that case, he may combine: he prays Dhuhr with the imam in four rak'ahs, then prays 'Asr in two rak'ahs, then walks. As for if he means by "Sunnah" the voluntary acts, then whoever reflects on the Sunnah will find that all voluntary acts from the Sunnah are done in the state of travel, except for the regular voluntary prayer of Dhuhr, the regular voluntary prayer of Maghrib, and the regular voluntary prayer of 'Isha', for which the Sunnah is not to perform them. As for the Sunnah of Fajr, the regular voluntary prayer of Fajr, it is a Sunnah for the traveler and the non-traveler. Likewise, Witr, the night prayer, the Duha prayer, the eclipse prayer, the prayer of Istikharah, and other voluntary prayers, their prescribed nature remains for the traveler as it is for the resident, except for the three regular voluntary prayers mentioned, which are the regular voluntary prayer of Dhuhr, the regular voluntary prayer of Maghrib, and the regular voluntary prayer of 'Isha', for which the Sunnah is not to perform them.