Question: What are the things that excuse a person from salat? Is it permissible for a person who has salats to make up to perform voluntary salats?
ANSWER
If one is unable to perform a salat even by combining two salats, then only the following situations excuse one from salat:

(1) if one, in front of the enemy during wartime, is unable to perform salat even by sitting and by turning to any direction other than the qibla; (2) when one is on a journey (safar); (3) if there is such a danger as floods, beasts, bandits, anarchists and if it is not possible to perform salat even by sitting or on an animal by gestures (ishaarah); (4) a midwife's missing salat due to delivery if the mother or her baby is to perish; (5) a doctor's missing salat due to an operation in case of emergency; (6) sleeping; (7) forgetting. It is not a sin to miss a salat due to such excuses. (Durr-ul-Mukhtar)

Not performing a salat within its prescribed time is haram and a major sin if there is no such an excuse.

The word faita (that is, a missed salat) is used in all fiqh books because a Muslim does not leave salat intentionally. He/she may miss it due to one of the abovementioned excuses. For this reason, the total number of one's missed salats can be few. However, today one's missed salats are many in number.

The ruling regarding a salat missed due to an excuse is different from the ruling regarding a salat not performed deliberately. As it is not a sin to miss a salat due to one of the abovementioned excuses, it will not be a sin to delay making it up as much as to perform sunnat and other nafila (voluntary) salats. The ruling regarding a salat missed due to an excuse, such as sleeping, forgetting, is as follows:

"Though it is better to make up the salats missed due to an excuse than to perform voluntary salats, the pre-fard and post-fard sunnat salats and the ones praised in hadith-i sharifs, such as Salat ad-Duha, Salat at-Tasbih, Tahiyyat al-Masjid, are not included in this ruling. It is better to perform them than to make up a missed salat" (Radd-ul-Mukhtar, Halabi, Fatawa-i Hindiyya).

The ruling regarding salats not performed deliberately is as follows:
"The great scholar Ibn Nujaym was asked: 'If a person who has salats omitted deliberately performs sunnats salats with the intention of making up his/her omitted salats, will he/she be considered to have left sunnat salats?' His answer was: 'He will not be considered to have left sunnat salats because one is considered to have carried out the sunnat when one performs any salat [nafila or qada] in addition to the fard'" (An-Nawadir-ul-Fiqhiyya fi Madhhab-il-Aimmat-il Hanafiyya, p. 36).

The sunnat salats of the five daily salats mean the salats performed by our Master the Prophet. These salats were termed sunnat salats later. When making intention for sunnat salats, the Messenger of Allah used to say only, "I intend to perform salat for the sake of Allah." He did not say, "I intend to perform a sunnat salat." Any salat performed in the time of a fard salat is considered the salat called sunnat. (Radd-ul-Mukhtar, Uyun-ul-Basair, Halabi)

It is stated in hadith-i sharifs:

(The best jihad is to perform fard [obligatory] acts of worship.) [Tabarani]

(The voluntary salat of a person who has a salat omitted will not be accepted.) [Durrat-ul-Fahira]

(When everybody spends time doing voluntary acts of worship, complete fard ones.) [Miftah-un-Najat]

(Allahu ta'ala said: "One cannot approach Me through anything as close as one approaches Me through fard acts of worship.") [Bukhari]

(If a person has a missed fard salat, his performing voluntary salat is like [the case of] a pregnant woman who has a miscarriage when she is about to give birth to her baby. The woman cannot be said to be pregnant, nor can she be called a mother anymore. So is this person. Unless he makes up his missed salats, Allahu ta’ala will not accept his voluntary salats.) [Zahira-i Fiqh, Futuh-ul-Ghayb] Abdulhaqq-i Dahlawi, a scholar of the Hanafi Madhhab, stated, "This hadith indicates that the sunnat salats of those who have salats omitted will not be accepted."

Hadrat Abd al-Qadir al-Ghaylani states:
"It is idiocy to spend time performing sunnat salats while one has salats to make up because the sunnats of a person who has salats omitted are not acceptable. A person performing the sunnats while he/she has debts of omitted salats is like a debtor taking a present to the person to whom he/she owes, which, normally, is not acceptable. A Believer is like a business person. The fard salats are his/her capital, and voluntary salats are his/her profit. Unless the capital is rescued, they will give no profit” (Futuh-ul-Ghayb).

It is written in the pamphlet entitled Bay wa Shir'a by Hadrat Hamza Efendi:
"Perform a two-rak'at salat before going on a journey. If you have salats to make up, then you must make up two or three salats because it is idiocy to perform voluntary salats when one has salats to make up" (p. 6).

Hadrat Imam-i Rabbani states:
"Voluntary acts of worship are of no value when compared with obligatory acts of worship. The value of a sunnat compared with a fard is not even like that of a drop of water compared with an ocean" (Letters 29, 260).

Hadrat Sayyid Abdulhakim Arwasi, who was an expert on the fiqh of the four madhhabs, said:
"One who has years of missed salats must perform sunnat salats with the intention of making up missed salats. Performing sunnat salats by intending in this way is necessary in all of the four madhhabs."

Allahu ta'ala says, "One approaches Me through fard acts of worship." His Messenger says, "The voluntary salat of a person who has a salat omitted will not be accepted." Islamic scholars say, "It is idiocy for a person who has salats omitted to perform sunnat and voluntary salats" and "When compared to those acts of worship that are fard, voluntary acts of worship are not even like a drop of water compared with an ocean." Those religiously ignorant people who equate salats that are not performed intentionally with salats missed due to an excuse encourage the layman to abandon the fards, which are Allahu ta'ala's commandments, and to perform voluntary acts of worship, such as Salat ad-Duha, Tayiyyat-ul-Masjid, Salat at-Tahajjud. If one does not perform these voluntary salats even once in one's lifetime, one will not be punished in the Hereafter. However, the punishment for neglecting to perform a single fard act of worship will be very severe.

"If one, when facing the enemy, does not perform a fard salat though it is possible to perform it, leaving it is equivalent to 700 major sins" (Jami'-ul-Fatawa).

The abovementioned fatwa proves that those who cause laymen to spend time doing voluntary acts of worship by making them delay or omit fard acts of worship shoulder a heavy responsibility.

Question: If one is unable to perform Salat al-Fajr at its due time and delays making it up until afternoon, will one incur a sin?
ANSWER
Yes, one will incur a sin. Delaying making up a fard salat is also a major sin.

Question: I often miss salats because of forgetting or oversleeping. Does forgetting excuse me from salat?
ANSWER
Forgetting and oversleeping are excuses. However, if one very often experiences forgetting, one will incur a sin if one does not take precautions. Some examples are as follows:

1. It is not excusable to miss Salat al-Fajr if one goes to bed extremely late without setting an alarm or taking other precautions.

2. If the time for a fard salat starts when one leaves the office and if one, though one knows that one will not be able to reach home before the time for it elapses, decides to perform it at home or if one, though one reaches home before the time for it elapses, often forgets to perform it when one is at home as one is used to performing it at the office, one is not excused from salat if one takes missing a salat lightly with the thought that forgetting is an excuse.

3. If one who turns toward the direction of the qibla during wudu' to comply with the sunnat, very often stretches one's feet toward the qibla forgetfully in the course of wudu', one should not turn toward the qibla when performing wudu' in order not to stretch one's feet toward the qibla because a sunnat must be omitted in order to avoid committing a makruh.