Rulings and issues about praying on a chair

Firstly: 

Standing, bowing and prostrating are pillars or essential
parts of the prayer. Whoever can do them, it is obligatory for him to do
them in the manner prescribed in sharee’ah. Whoever is not able to do them
because of sickness or old age, it is Sunnah for him to sit on the ground or
on a chair. 

Allaah says (interpretation of the meaning): 

“Guard strictly (five
obligatory) As‑Salawaat (the prayers) especially the middle Salaah (i.e. the
best prayer ‑ ‘Asr). And stand before Allaah with obedience [and do not
speak to others during the Salaah (prayers)]”

[al-Baqarah 2:238] 

It was narrated that ‘Imraan ibn Husayn (may Allaah be
pleased with him) said: I had haemorrhoids so I asked the Prophet
(peace and blessings of Allaah be upon him) about praying. He said: “Pray
standing up; if you cannot, then pray sitting down; and if you cannot, then
pray (lying) on your side.” Narrated by al-Bukhaari, 1066. 

Ibn Qudaamah al-Maqdisi said: 

The scholars are unanimously agreed that if a person cannot
stand then he may pray sitting down. Al-Mughni, 1/443 

Al-Nawawi said: 

The ummah is unanimously agreed that whoever is unable to
stand during the obligatory prayer may pray sitting, and he does not have to
repeat it. Our companions said: his reward will not be less than the reward
for praying standing, because he is excused. It is proven in Saheeh
al-Bukhaari that the Messenger of Allaah (peace and blessings of
Allaah be upon him) said: “If a person is sick or travelling, the same
reward will be written for him with regard to what he used to do when he was
not travelling and was healthy.”

Al-Majmoo’, 4/226 

Al-Shawkaani said: 

The hadeeth of ‘Imraan indicates that it is permissible for
one who has an excuse and cannot stand to pray sitting, and for one who has
an excuse and cannot pray sitting to pray lying on his side.

Nayl al-Awtaar, 3/243 

Shaykh al-Islam Ibn Taymiyah said: 

The Muslims are agreed that if a worshipper is unable to do
some of the obligatory duties of prayer, such as standing, reciting, bowing,
prostrating, covering the ‘awrah, facing the qiblah etc, then what he is
unable to do is waived for him. End quote from Majmoo’ al-Fataawa,
8/437 

Based on that, if a
person offers an obligatory prayer sitting when he is able to stand, his
prayer is invalid. 

Secondly: 

It should be noted that if a person is exempted from
standing, his excuse does not make it permissible for him to sit on the
chair to bow and prostrate. 

If he is exempted from bowing and prostrating in the proper
manner, that excuse does not make it permissible for him not to stand and to
sit on the chair instead. 

The basic principle with regard to the obligatory duties of
prayer is that whatever the worshipper can do, he is obliged to do it, and
whatever he is unable to do, is waived for him. 

Whoever is unable to stand, it is permissible for him to sit
on a chair during the standing, and he should bow and prostrate in the
proper manner. If he is able to stand but it is difficult for him to bow and
prostrate, he should pray standing, then sit on the chair when bowing and
prostrating, and he should bend lower for the prostration than for the
bowing.  

See also question no. 9307 and
36738. 

Ibn Qudaamah al-Maqdisi said: 

If a person is able to stand but he cannot bow or prostrate,
the standing is not waived for him; he should pray standing and tilt his
head for the bowing, then sit down and tilt his head for the prostration.
This is the view of al-Shaafa’i… 

Because Allaah says (interpretation of the meaning):
“And stand before Allaah with obedience” [al-Baqarah 2:238],
and the Prophet (peace and blessings of Allaah be upon him) said: “Pray
standing.” And because standing is one of the pillars (essential parts of
prayer) for the one who is able to do it, so he must do it, like the
recitation. Being unable to do other things does not mean that this is
waived, as is also the case if he is unable to recite. End quote from
al-Mughni, 1/44. 

Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allaah have mercy on him)
said: 

The one who prays sitting on the ground or on a chair must
make his prostration lower than his bowing. The Sunnah is for him to put his
hands on his knees when bowing, and when prostrating the Sunnah is to put
them on the ground if possible; if he cannot do that then he should put them
on his knees, because it was proven that the Prophet (peace and
blessings of Allaah be upon him) said: “I have been commanded to prostrate
on seven bones: the forehead – and he pointed to his nose – the two hands,
the two knees, and the edges of the two feet (i.e., the toes).” 

If a person is unable to do that and prays on a chair, there
is nothing wrong with that, because Allaah says (interpretation of the
meaning): 

“So keep your duty to
Allaah and fear Him as much as you can”

[al-Taghaabaun 64:16] 

and the Prophet (peace and blessings of Allaah be upon
him) said: “If I tell you to do a thing, then do as much of it as you can.”
Saheeh – agreed upon. 

Fataawa Ibn Baaz,
12/245, 246. 

Thirdly: 

With regard to the placement of the chair in the row, the
scholars (may Allaah have mercy on them) stated that the one who prays
sitting down should have his posterior in line with the row when he is
sitting, so he should not be in front of the row or behind it at that point,
because that is the place in which the body settles. 

See Asnaa al-Mataalib,
1/222; Tuhfat al-Muhtaaj, 2/157;
Sharh Muntaha al-Iraadaat,
1/279. 

It says in al-Mawsoo’ah
al-Fiqhiyyah (6/21): 

In order for a person’s following the imam to be valid, he
should not stand in front of the imam according to the majority of fuqaha’
(Hanafis, Shaafaa’is and Hanbalis). 

How do we know whether he is in front of the imam or not, it
is judged by where the heels are. If they are standing level at the heel and
the toes of the one who is praying behind the imam turn out to be in front
because he has longer feet, that does not matter. With regard to those who
are sitting, it is judged by where the posterior is. And with regard to
those who are praying on their sides, it is judged by their sides.   

If the worshipper is going to pray on the chair from the
beginning of the prayer until the end, then he should make the place where
he will sit level with the row. 

If he is going to pray standing, but he will sit on the chair
when he bows and prostrates, we asked Shaykh ‘Abd al-Rahmaan al-Barraak
about that, and he said that what matters here is the standing position, so
he should be level with the row when standing.  

Based on this, the chair will be behind the row, so it should
be placed in such a manner that it will not disturb worshippers in the row
behind. 

And Allaah knows best.