Abu Dawud

926. Commentary:
➊ In Sahih Muslim, Book of Mosques, Hadith [540], it is mentioned that Zuhair clarified the gesture of the Prophet sallallahu alayhi wa sallam by pointing towards the ground.
➋ While traveling, (supererogatory) prayers can be performed on a mount, and the bowing (ruku) and prostration (sujud) will be done by gestures.
➌ During the prayer, it is permissible to respond to someone by means of a gesture.
➍ If someone is unable to respond for some reason, he should present an excuse.

1191. Commentary: This narration is a detailed explanation of the previous narration. It appears that Jabir (radi Allahu anhu) did not understand that a gesture could serve as a reply to the greeting of peace (salam), because at that initial stage, replying verbally to the greeting had been prohibited.

Hadith Commentary:
In the narration of Muslim, it is mentioned that this incident took place during the expedition of Banu al-Mustaliq.
And in another narration of Muslim, it is also clarified that the Prophet (sallallahu alayhi wa sallam) responded with a gesture of the hand, and the reason for Jabir's (radi Allahu anhu) sadness and worry was that he did not understand that this gesture was a reply to the greeting of salam.
Because previously, the reply to salam was given verbally, not by gesture.

Hadith Commentary:
In the narration of Sahih Muslim, it is mentioned that the Messenger of Allah (sallallahu alayhi wa sallam) responded to the greeting (salam) of Jabir (radi Allahu anhu) with a gesture of the hand, which Jabir (radi Allahu anhu) could not understand; thus, he became worried and thoughtful.
(Sahih Muslim, al-Masajid, Hadith: 1205(540), and Fath al-Bari: 113/3)
The purpose of Imam Bukhari (rahimahullah) with this chapter heading and hadith is that when a person praying is greeted with salam during the prayer, he should not respond verbally.
His intention is certainly not that it is disliked (makruh) to greet someone praying with salam, or that responding is impermissible, because from other ahadith it is established that during prayer, responding to salam with a gesture of the hand is proven. Thus, it is narrated from Ibn Umar (radi Allahu anhu), he said:
I asked Bilal (radi Allahu anhu), "When people used to greet the Messenger of Allah (sallallahu alayhi wa sallam) with salam during prayer, how would he respond to them?" He said:
He would do like this, and he spread out his hand, meaning he would respond with a gesture of the hand.
(Sunan Abi Dawud, al-Salat, Hadith: 927)

Fiqh al-Hadith
It is permissible and valid to greet a person performing prayer (salah) with salam, and during the state of prayer, it is Sunnah to reply to the salam not verbally, but with a gesture. Replying to salam verbally during prayer has been abrogated.
↰ This hadith proves that it is permissible to greet a person performing prayer with salam and to reply with a gesture.

«ان عبدالله بن عمر على رجل، و هو يصلي، فسلم عليه فرد الرجل كلاما، فرجع اليه عبدالله بن عمر، فقال له : اذا سلم على احد كم، وهو يصلي، فلا يتكلم وليشر بيده۔۔»
“Sayyiduna Abdullah ibn Umar radi Allahu anhuma passed by a man who was performing prayer. He greeted him with salam, and the man replied verbally. Sayyiduna Abdullah ibn Umar radi Allahu anhuma turned back to him and said: When one of you is greeted with salam while he is performing prayer, he should not speak, but rather reply with a gesture of his hands.” [الموطا للامام مالك : 168/1، مصنف ابن ابي شيبه : 74/2، ح : 4749، اسناده صحيح كالشمس وضوحاًً]

An Objection from the Prohibitors ➑
SA «عن جابر بن عبدالله رضى الله عنه، قال : بعثني رسول الله صلى الله عليه وسلم فى حاجة له، فانطلقت، ثم رجعت، وقد قضيتها، فا اتيت النبي صلى الله عليه وسلم فسلمت عليه، فلم يرد علي، فوقع فى قلبي ما الله اعلم به، فقلت فى نفسي : لعل رسول الله صلى الله عليه وسلم وجد علي أني أ بطأت عليه، ثم سلمت عليه، فلم يرد علي، فوقع فى قلبي أشد من المره الأولي، ثم سلمت عليه، فرد علي، فقال : انما منعني أن أرد عليك أني كنت اصلي، و كان على راحلته متوجها الي غير القبلة۔»
“Sayyiduna Jabir ibn Abdullah radi Allahu anhu narrates that the Messenger of Allah sallallahu alayhi wa sallam sent me for some task. After completing the task, I returned to the presence of the Prophet sallallahu alayhi wa sallam and greeted him with salam, but he did not reply to my salam. Allah alone knows the state of my grief and sorrow; I thought to myself that perhaps the Messenger of Allah sallallahu alayhi wa sallam was displeased with me due to my delay. I greeted him with salam again, but he did not reply. My heart was filled with even more grief and sadness than before. Then, after the Prophet sallallahu alayhi wa sallam finished his prayer and turned in salam, I greeted him again, and he replied and said: Indeed, only prayer prevented me from replying to your salam.” [صحيح بخاري : 1217، صحيح مسلم : 540]
Janab Thanawi writes:
«فآنه قد صريح فى أنه صلى الله عليه و سلم لم يرد على جابر، لا اشاره ولا لفظا ولو كان رد عليه اشارة لم يقع فى قلب جابر ما وقع، فتقييده بالكلام غير سديد، و أيضا لو كان صلى الله عليه وسلم رد عليه بالاشاره لم يحتج الي رد عليه بعد الفراغ ‘كما هو مذهب من يجير الرد با لاشارة، و قد ثبت أنه رد عليه بعد ما انصرف عن صلاته، و هو الماثور من مذهب الجابر۔۔۔»
This clearly indicates that the Prophet sallallahu alayhi wa sallam neither replied to Sayyiduna Jabir with a gesture nor verbally. If he had replied with a gesture, Sayyiduna Jabir radi Allahu anhu would not have felt grief and sorrow in his heart. To restrict this to the view that the reply to salam was by gesture and not by speech is not a firm opinion. Likewise, if the Prophet sallallahu alayhi wa sallam had replied to the salam with a gesture, then what need was there to reply verbally after completing the prayer? Whoever considers replying to salam with a gesture permissible does not do so (i.e., does not reply verbally after the prayer). It is established from the Prophet sallallahu alayhi wa sallam that he replied to the salam after completing the prayer. This was also the view of Sayyiduna Jabir radi Allahu anhu. [اعلاء السنن : 33/5] EA SH Answer: EH
Thanawi Sahib’s statement is not based on reality, because in the narration of Sahih Muslim it is mentioned that the Prophet sallallahu alayhi wa sallam replied to Sayyiduna Jabir radi Allahu anhu’s salam with a gesture of the hand. This also clarifies the meaning of the narration in Sahih Bukhari, because the ahadith explain one another. As for the issue of why Sayyiduna Jabir radi Allahu anhu felt grief in his heart, Hafiz Ibn Hajar rahimahullah writes:
«فيحمل فى حديث الباب ”فلم يرد علي“ أى باللفظ،، وكان جابر الم يعرف اولا أن المراد بالاشارة الرد فلذلك قال : فوقع فى قلبي ما الله اعلم به، أى من الحزن۔»
“Sayyiduna Jabir radi Allahu anhu’s statement that the Prophet sallallahu alayhi wa sallam did not reply to me means that he did not reply explicitly (i.e., verbally). It is as if, at first, Sayyiduna Jabir radi Allahu anhu did not know that a gesture constituted a reply, and that is why he said that such grief and sorrow arose in his heart as only Allah knows.” [فتح الباري لابن حجر : 87/3]
↰ Thanawi Sahib’s claim that restricting the lack of reply to verbal speech is not a firm opinion is refuted by the hadith in Sahih Muslim, and other ahadith and athar also contradict it. As for why the Prophet sallallahu alayhi wa sallam felt the need to reply to the salam after the prayer, it is clear from the narration that Sayyiduna Jabir radi Allahu anhu greeted him with salam both during the prayer and after he had finished. During the prayer, the Prophet sallallahu alayhi wa sallam replied with a gesture, and after completing the prayer, he replied verbally. Thanawi Sahib could not understand this simple matter and thus resorted to interpreting the hadith.
SA Zafar Ahmad Thanawi Sahib has mentioned that the view of Sayyiduna Jabir radi Allahu anhu was that if someone greets a person performing prayer with salam, he should only reply after completing the prayer. EA The evidence he has provided for this is “weak,” as has already been explained earlier. Even if Thanawi Sahib’s statement is accepted as correct, it would mean that it is permissible to greet a person performing prayer with salam; if he does not reply, there is no harm, and if he does, it is permissible, and he may reply with a gesture. Replying verbally is prohibited. We also do not consider replying to salam with a gesture during prayer to be obligatory, but only hold its permissibility.

Hadith Commentary: Benefits and Issues: The battle with the tribe of Mustaliq took place in the 5th or 6th year of Hijrah.