Muslim

Explanation:
Since, in reality, iman (faith) and Islam are one and the same, therefore from the question of «اي الاسلام افضل» it is understood that iman increases and decreases. There is a lower (adna) in comparison to a higher (afdal). Thus, Islam—in terms of iman, righteous deeds (a‘mal salihah), and pure character (akhlaq pakizah)—continues to increase and decrease. This is precisely the intent of the Imam here.

Hadith Commentary:
1.
The genitive (mudaf ilayh) of "ayy" is something in which there is multiplicity, but "Islam" is singular? The answer to this is that here the genitive is omitted (hazf mudaf). We have made the original phrase explicit in the translation. That is, (ayy sahib al-Islam afdal) — "Which possessor of Islam is best?" Thus, the question pertains to the person. This is why the answer is also given regarding the person. This is supported by another narration whose words are: "Which Muslim is best?" (Sahih Muslim, Al-Iman, Hadith: 163(42)). By doing so, there is conformity between the question and the answer.

2.
From this very narration in Sahih Muslim, it is also clear that the one asking the question to the Messenger of Allah (sallallahu alayhi wa sallam) is the very narrator of the hadith, Abu Musa al-Ash'ari (radi Allahu anhu). From some other narrations, it is known that this type of question was also asked by Abu Dharr al-Ghifari (radi Allahu anhu) and Umair ibn Qatadah (radi Allahu anhu). There is no contradiction in these narrations, because sometimes they explicitly mentioned the name, and sometimes they attributed the question to other people, since they were in agreement regarding this question, and being in agreement with someone is as if one has asked the question oneself. (Fath al-Bari: 1/77)

3.
This narration also clarifies the previous hadith, from which it seemed that the restriction (hasr) was in terms of reality. From this narration, it is understood that the restriction is not in terms of reality, but rather in terms of perfection (kamal), meaning that there are differences in the ranks of Muslims: some are more perfect (akmal), and some are perfect (kamil). That is, the Muslim who, along with other Islamic symbols, also possesses the attribute mentioned in the narration, he is superior and more perfect. And Allah knows best.

Explanation: 1:

The meaning of being safe from one's tongue is that he does not use his tongue to taunt or insult any Muslim, nor to backbite, slander, or spread calumny, nor to abuse or curse him.
And the meaning of being safe from one's hand is that he does not strike anyone with his hand, nor kill, nor unjustly break anyone's property, nor write any text containing false ideas by which people may be led astray.

The purpose of the author rahimahullah in this chapter is to show that not all Muslims are equal in Islam and faith (iman); rather, the Islam and iman of some are greater, while that of others is lesser. This increase and decrease occurs both in terms of actions and in terms of the state of the heart. The meaning of “Which Islam is best?” is: who among the people of Islam is the most virtuous.