Nasai

Whoever becomes unable to fulfill his vow must offer expiation (kaffarah). For details, see narration: 3845.

Hadith Commentary:

It is commanded to break such an unlawful vow (nadhar) that exceeds the bounds of moderation. This person’s father was paralyzed, and he had vowed to perform Hajj by walking with the support of his two sons’ shoulders. The Prophet (sallallahu alayhi wa sallam) forbade him from walking in this manner.

Hadith Commentary:
(1)
The aforementioned narration has already been detailed previously, that the Messenger of Allah (sallallahu alayhi wa sallam) saw a man who was walking with the support of his two sons. So he (sallallahu alayhi wa sallam) inquired:
“What has happened to him?” They replied:
“He had vowed to walk on foot.”
The Messenger of Allah (sallallahu alayhi wa sallam) said:
“He has unnecessarily put himself in hardship.
Allah, the Exalted, is independent of his self-imposed suffering.”
Then he (sallallahu alayhi wa sallam) ordered him to ride (i.e., to mount an animal).
(Sahih al-Bukhari, Book of Hajj, Hadith: 1865) (2)
It appears that the man was unable to walk on foot.
Perhaps his legs were paralyzed.
In any case, the Messenger of Allah (sallallahu alayhi wa sallam) forbade fulfilling such vows in which the intention is to put oneself in hardship.
And Allah knows best.

Hadith Commentary:
The purpose of the Prophet’s (sallallahu alayhi wa sallam) repeated statement is to clarify that riding on the sacrificial camel does not contradict its status as one of the symbols (sha‘a’ir) of Islam.

Hadith Commentary:

(1)
From these ahadith, it is understood that riding on the sacrificial animal is permissible, whether the sacrifice is obligatory or voluntary, because the Messenger of Allah (sallallahu alayhi wa sallam) did not inquire from the owner of the sacrifice about such a distinction. This means that the ruling for both obligatory and voluntary sacrifice is the same.

Hazrat Ali (radi Allahu anhu) was asked about riding on the sacrificial animal. He replied: There is no harm in it, because whenever the Messenger of Allah (sallallahu alayhi wa sallam) passed by people who were walking, he would instruct them to ride on their sacrificial animals.

In this matter, necessity should be taken into consideration, and when the need is over, they should not be used for riding, as is mentioned in the hadith of Sahih Muslim, where the Messenger of Allah (sallallahu alayhi wa sallam) said: “Ride on the sacrificial animal in a good manner when you are in need of it, until you find another mount.” (Sahih Muslim, Al-Hajj, Hadith: 3214(1324))

The meaning of this hadith is that if another mount is available, the sacrificial animal should be set free. Accordingly, Imam Bayhaqi (rahimahullah) has established a chapter with these words: (يركب إذا اضطر ركوبا غير قادح) “When there is a need for riding, it is permissible to ride on the sacrificial animal.” However, these animals should not be given for hire as mounts. (Fath al-Bari: 3/679)

(2)
In fact, in the era of ignorance (Jahiliyyah), people would leave some animals as religious offerings. Riding on them was considered objectionable among them. The same notion existed regarding sacrificial animals. Islam declared this to be incorrect, because being a sacrificial animal does not at all mean that it should be rendered completely useless. The Messenger of Allah (sallallahu alayhi wa sallam) repeatedly insisted and commanded that one should ride on it, so that one may be protected from fatigue on the way.

Islam is a religion of nature (fitrah), and at every step, it has taken human needs into consideration.

Hadith Commentary:

So, is it obligatory to fulfill such a vow or not? From the hadith, it is understood that fulfilling such a vow is not obligatory, because performing Hajj while riding is superior to performing it on foot. Or, the Messenger of Allah (sallallahu alayhi wa sallam) ordered him to ride because he did not have the strength to walk on foot.

Hadith Commentary:
(1)
Some commentators have stated that the name of this old man was Abu Isra’il, but this is not correct because Abu Isra’il did not vow to walk on foot; rather, his vow was that he would not use anything for shade, would not speak to anyone, and would fast. He was standing in the sun on Friday, so the Messenger of Allah (sallallahu alayhi wa sallam) inquired about him. In the mentioned hadith, a different incident is narrated.

(2)
The scholars differ regarding whether performing Hajj on foot is more virtuous or performing it while riding is more meritorious. If performing Hajj while riding is more virtuous, then in the aforementioned vow, there is an adherence to abandoning what is superior; and if performing Hajj on foot is more virtuous, then the Messenger of Allah (sallallahu alayhi wa sallam) ordered him to ride due to his inability. In any case, the Messenger of Allah (sallallahu alayhi wa sallam) did not order this old man to fulfill his vow.
(Fath al-Bari: 4/103)

1:
This was said by you as a warning and a rebuke, because you had already granted him permission to ride, and you already knew that this was a sacrificial animal (hady).

Urdu marginal note:
"He was commanded" because he was unable to walk. Whoever is able to walk should walk; if he becomes unable, then he should ride and give expiation (kaffarah).

If there is hardship in walking, then there is no harm in riding the sacrificial animal. If the journey is long, this too is a form of hardship. It is not necessary that one be completely unable to walk in order to ride; one may ride when there is a need. However, if a separate mount is available, then one should not ride the sacrificial camel. Respect is necessary.

Explanatory Notes and Issues:

➊
Hady refers to the animal that a pilgrim brings along with him in order to slaughter it in Mecca or Mina on the days of sacrifice.

➋
It is permissible to ride the sacrificial animal when there is no other means of riding available and the person has become tired. In a narration from Jabir radi Allahu anhu, the Messenger of Allah sallallahu alayhi wa sallam said:
"Ride it in a good manner when you are compelled to do so, until you find another animal to ride." (Sahih Muslim, Book of Hajj, Chapter: The Permissibility of Riding the Sacrificial Camel for One Who Needs It, Hadith: 1324)