When you travel through the land, it is permissible for you to shorten the prayer31—˹especially˺ if you fear an attack by the disbelievers. Indeed, the disbelievers are your sworn enemies.
When you travel through the earth, there is no blame on you if you shorten your prayers, 617 for fear the Unbelievers May attack you: For the Unbelievers are unto you open enemies.
617 Verse 101 gives permission to shorten congregational prayers when people are on a journey: verses 102-104 deal with cases when they are in danger at war, in face of the enemy. The shortening of congregational prayers in both cases is further governed as to details by the practice of the Messenger and his companions. As to journeys, two questions arise: (1) what constitutes a journey for this purpose? (2) is the fear of an attack an essential condition for the shortening of the congregational prayers? As to (1), it is best to leave the matter to discretion, having regard to all the circumstances of the journey, as in the case of the journeys which excuse a fast see 2:184, n. 190. The text leaves it to discretion. As to (2), the practice of the Prophet shows that danger is not an essential condition: it is merely mentioned as a possible incident. The Messenger usually shortened the prayers from four Rak'ahs to two Rak'ahs in Zuhr ( midday prayer). ( Asr (afternoon prayer) and 'Isha' (night prayer): the other two are in any case short, Fajr (morning prayer) having two Rak'ahs and Maghrib (evening prayer) having three. (R).
AND WHEN you go forth [to war] on earth, you will incur no sin by shortening your prayers 127 if you have reason to fear that those who are bent on denying the truth might suddenly fall upon you: 128 for, verily, those who deny the truth are your open foes.
127 Lit., "the prayer": a reference to the five obligatory daily prayers - at dawn, noon, afternoon, after sunset and late in the evening - which may be shortened and combined (the noon prayer with that of the afternoon, and the sunset prayer with that of the late evening) if one is travelling or in actual danger. While the extension of this permission to peaceful travel has been authorized by the Prophet's sunnah, the Qur’an mentions it only in connection with war situations; and this justifies the interpolation, in the opening sentence, of the words "to war". The prayer described in the next verse - with the congregation praying in shifts - is called salat al-khawf ("prayer in danger").
128 Lit., "might cause you an affliction" - implying, according to almost all the commentators, a sudden attack.
31 Generally, it is permissible for Muslims who are travelling a distance of 85 km or more to shorten their prayers. A four-unit prayer is reduced to two.