First: The default principle in acts of worship—such as prayer, fasting, Ḥajj, and others—is that they must be completed and properly performed. Allāh says: “And complete the Ḥajj and ‘Umrah for Allah.” [Al-Baqarah 2:196]
“So that you may complete the prescribed period and glorify Allāh for guiding you.” [Al-Baqarah 2:185]
“O you who believe, obey Allāh and obey the Messenger and do not invalidate your deeds.” [Muḥammad: 33]
Thus, by observing the command of fulfilling the act of worship and the prohibition against nullifying it lies the perfection of the act.

The Prophet (peace and blessings be upon him) said: “Indeed, Allāh loves that when any one of you does a deed, he perfects it.”
Perfection includes completing the act without deficiency or nullification.

Second: There are certain circumstances that may arise for a worshiper where it is permissible to stop the act of worship, and others where it is not. The details are as follows:

1. Cutting off an obligatory prayer for a valid legal reason:

The justification must be tied to the loss of one of Maqāṣid ash-Sharī῾ah (the higher objectives of Sharī῾ah), such as cutting the prayer due to a threat to one’s life, wealth, or honor. In such cases, it is permissible to cut off the prayer to prevent harm, and one does not need to repeat what was already prayed, but may resume from where they left off if the interruption was not long.

For example:

• Interrupting prayer to extinguish a fire: one may resume after putting it out.
• Interrupting to kill a snake or scorpion is permissible, based on Prophet Muḥammad’s command of to kill them.
• Interrupting to seek protection from a wild dog, or to avoid something falling on the person while in prostration.
• Interrupting to prevent loss of valuable property, whether for oneself or others.
• Helping someone in need, such as an elderly blind person who may fall, or alerting a sleeping or unaware person of an imminent danger from a human or animal—especially when it is not possible to alert them with tasbiḥ (to say “subḥān Allāh”).
• Interrupting a fast to save a drowning person, or a nursing woman breaking her fast out of fear for herself or her infant.

In all such cases, the prayer can be resumed if the interruption did not take a long time. If it takes a long time, then a new prayer must be started, but the other one – which was cut off – is not to be repeated—since an obligatory prayer does not turn into another obligatory prayer.

2. Cutting off an obligatory prayer for a perceived or subjective justification:

This includes the scenarios mentioned in the question—such as leaving the prayer because the place is uncomfortable, too hot, noisy, or to answer the phone, even if one is expecting a call. This is not permissible, and the person who does so has sinned and must seek forgiveness. However, the only obligation is to perform the obligatory prayer again.

3. Cutting off nafl (a voluntary prayer) for a valid justification:

The same rulings apply as with obligatory prayers. However, there is a further discussion:

• According to the Ḥanafī and Mālikī schools, once a person starts a voluntary act of worship with intention and actions, it becomes binding and must be completed, and if interrupted, it must be made up in the same form.
• According to the Shāfi῾ī and Ḥanbalī schools, there is no obligation to make it up.

The latter cites the ḥadīth of Fākhitah bint Abī Ṭālib (᾽Umm Hāni᾽), who reported that the Prophet (peace and blessings be upon him) said: “The one performing a voluntary fast is the master of himself: if he wishes, he may fast, and if he wishes, he may break it.” However, this proof is countered by the narration from Abī Hurayrah, who said the Prophet (peace and blessings be upon him) said: “If one of you is invited to a meal, let him respond; if he is not fasting, let him eat; and if he is fasting, let him pray.” The phrase “let him pray” here means to supplicate for the host’s blessing and apologize for not eating due to fasting.

4. Cutting off a voluntary prayer without a valid excuse:

The same previous disagreement applies here:

• The Ḥanafī and Mālikī schools prohibit it and require that the prayer be made up.
• The Shāfi῾ī and Ḥanbalī schools permit it without obligation of making it up.

To conclude, the reason mentioned in the question—discomfort, noise, heat, etc.—is not a valid justification for interrupting an obligatory prayer. The only exception is if one wishes to wake someone up who may miss the prayer, provided that by doing so, they themselves do not miss the prayer time.

Fatwā issued by Dr. Khālid Naṣr