Nasai

1936. Commentary: The necessary conditions for testimony must be present in them, that is, they should be upright (ʿadl) Muslims. By upright (ʿadl) is meant that they are observant of the prescribed religious duties (shar‘i obligations) and safeguarded from major sins (kabirah). It is evident that only witnesses of this kind will give truthful testimony.

Hadith Commentary:
From this hadith, Imam Bukhari rahimahullah deduced that for the validation and declaration of uprightness (ta'dil and tazkiyah), the testimony of at least two persons is necessary.
This is also the opinion of Imam Malik and Imam Shafi'i.
However, according to Imam Abu Hanifah, the testimony of even one person is sufficient.
(Qastallani)
The meaning of the hadith is that for the one whom the Muslims praise, Paradise becomes obligatory for him, and for the one whom they criticize, Hell becomes obligatory for him.
This means the approval of public opinion.
It is true that the voice of the people is called the drum of God.
The purpose of the absolute mujtahid Imam Bukhari in bringing these narrations is to show that public opinion has a significant role in validation and declaration of uprightness (ta'dil and tazkiyah).

Hadith Commentary:
In this hadith, Umar radi Allahu anhu repeated what the Messenger of Allah sallallahu alayhi wa sallam had stated. However, in this narration, the number of those who testify to someone being good or bad is mentioned: if two believers testify regarding someone, their testimony will be accepted. From this, it is understood that for ta'dil (affirmation of uprightness), the testimony of at least two people is sufficient. However, it is necessary that those who give testimony possess good character and exemplary beliefs and views.

From other chapter headings of Imam Bukhari rahimahullah, it is evident that he considers the testimony of a single person sufficient for tazkiyah (attestation of integrity).

And Allah knows best.

Hadith Commentary:
The purpose of the chapter is that mentioning the virtues of the deceased and remembering them with good words is preferable.

Allamah Ibn Hajar rahimahullah states:
In the narration of al-Nadr ibn Anas from his father, as recorded by al-Hakim: “I was sitting with the Prophet sallallahu alayhi wa sallam when a funeral procession passed by. He sallallahu alayhi wa sallam asked, ‘Whose funeral is this?’ The people replied, ‘It is the funeral of so-and-so, who used to love Allah and His Messenger, and would act in obedience to Allah and strive in it.’ And regarding the one about whom evil was spoken, the opposite was said. Thus, in this narration, there is an explanation of what was ambiguous regarding good and evil in the narration of Abd al-Aziz. Al-Hakim also narrates from the hadith of Jabir: Some of them said, ‘What an excellent man! He was indeed chaste and a Muslim.’ And regarding another, it was said, ‘What a bad man he was! He was harsh and coarse in speech.’”
(Fath al-Bari)

That is, in the Musnad of al-Hakim, in the narration of al-Nadr ibn Anas from his father, it is mentioned that I was sitting with the Prophet sallallahu alayhi wa sallam when a funeral procession passed by. He sallallahu alayhi wa sallam asked, “Whose funeral is this?” The people said, “It is so-and-so, who loved Allah and His Messenger, acted in obedience to Allah, and strove in it.” And regarding the one about whom evil was mentioned, the opposite was said about him. Thus, in this narration, the details of what was ambiguous regarding good and evil are mentioned. And in al-Hakim, the hadith of Jabir is also as follows: Some people said, “This person was a very good, chaste Muslim,” and regarding another, it was said, “He was a bad man, ill-mannered, and harsh in speech.”

In summary, the testimony of the righteous believers regarding the deceased, in whatever manner it is given, carries great weight. The words “You are Allah’s witnesses on earth” point to this very reality.

This subject is also mentioned in the Qur’an in these words:
“And thus We have made you a middle nation so that you may be witnesses over mankind.” (al-Baqarah)

One form of testimony is also that which is mentioned here in the hadith.

Hadith Commentary:
(1)
No question was asked regarding the testimony of one man because the minimum requirement (nisaab) for testimony is two men. Thus, Imam Bukhari rahimahullah has also established the requirement of testimony from this hadith.
(Sahih al-Bukhari, al-Shahadat, Hadith: 2643)
It should be clear that, regarding the deceased, the testimony of only those people will be considered valid who are religious and trustworthy, because those who are immoral and involved in wickedness and sin will only praise those like themselves.
And the testimony of those people who have enmity or jealousy towards the deceased will also not be valid, because the testimony of an enemy is not considered reliable.

(2)
In one hadith it is mentioned that when a person passes away and his four close neighbors testify regarding him that they did not know anything about him except good, then Allah Ta’ala says: I have accepted your statement, and I have forgiven the faults and sins which you did not know about.
(Musnad Ahmad: 242/3)
There is no doubt that the praise of people for the deceased is a good sign.
From this, it is also understood that, when needed, a person’s good or bad qualities can be mentioned, and doing so does not fall under the prohibited backbiting (gheebah).
(Fath al-Bari: 294/3)