Tirmidhi

Explanation:
1:
Based on this hadith, some people argue that anyone who arrives after victory has been achieved but before the distribution of war booty (mal-e-ghanīmah) should also be given a share.

Hadith Commentary:
From one (group) from Makkah to Abyssinia, and from another (group) from Abyssinia to Madinah.
In the narration of Muslim, it is mentioned that the Prophet (sallallahu alayhi wa sallam) did not allocate a share from the spoils of Khaybar to those who had not participated in that battle, except for our companions of the ship, to whom he gave a share along with Ja‘far ibn Abi Talib (radi Allahu anhu).

Hadith Commentary:
1.
Abu Musa al-Ash‘ari (radi Allahu anhu) first migrated to Makkah. When he accepted Islam, the Messenger of Allah (sallallahu alayhi wa sallam) sent him along with others towards Abyssinia (Habashah). Instead of going to Abyssinia, he turned towards the region of his own people, which is on the eastern side, opposite Abyssinia. When he received news that the Messenger of Allah (sallallahu alayhi wa sallam) had moved to Madinah Tayyibah, he, along with the Muslims of his people, boarded a boat and set out towards Madinah Tayyibah. However, the sea waves carried them to Abyssinia, so they stayed there with Sayyiduna Ja‘far (radi Allahu anhu). Later, they reached Madinah Tayyibah at the time when Khaybar had already been conquered.
(Fath al-Bari: 7/237)

2.
These are the two migrations:
One is from Makkah al-Mukarramah to Abyssinia, and the second is from Abyssinia to Madinah Tayyibah. For those who did not migrate to Abyssinia, there was only one migration, which was from Makkah to Madinah Tayyibah.

Hadith Commentary:
Apparently, this portion was given to him by the Prophet (sallallahu alayhi wa sallam) from the spoils of war (mal-e-ghanīmah) itself, not from the khums. Then how does this relate to the chapter heading? However, when it is permissible for the Imam to dispose of the spoils of war—which are the right of the other warriors—in such a manner, then it is even more permissible (a fortiori) in the case of the khums, which is specifically entrusted to the Imam.
Thus, the purpose of the chapter is fulfilled.

Hadith Commentary:
The various explanations given by the scholars of the Ummah regarding the share from the spoils of war (ghanimah) that was given to Abu Musa al-Ash‘ari (radi Allahu anhu) and his companions, as well as those who came along with Ja‘far (radi Allahu anhu), are detailed as follows:

➊ The Messenger of Allah (sallallahu alayhi wa sallam) gave a share from the spoils to those who were formally entitled to it after taking them into confidence, just as he had given to the people of the tribe of Hawazin, and he had satisfied his Companions regarding this.

➋ The Messenger of Allah (sallallahu alayhi wa sallam) gave them a share from the wealth that was acquired without battle, because the entirety of Khaybar was not conquered by force; rather, some areas came under control through peace agreements. The Messenger of Allah (sallallahu alayhi wa sallam) gave these individuals a share from the khums (one-fifth portion), because it is not reported that he sought permission from those who participated in the Battle of Khaybar.

➌ This also appears to be the inclination of Imam al-Bukhari (rahimahullah), because he mentioned this hadith under the chapter heading he established. And Allah knows best.

Hadith Commentary:
In one narration, it is stated that whoever was absent at the conquest of Khaybar was not allotted a share from the wealth of Khaybar; only those who were present at Khaybar received a share. However, for the People of the Ship (Ahl al-Safina), including Ja‘far (radi Allahu anhu) and his companions, a share from the spoils of Khaybar was allotted to all of them.
(Fath al-Bari: 7/608.)

By "People of the Ship" (Ahl al-Safina) is meant Abu Musa (radi Allahu anhu) and his companions.
They were given a share from the wealth of Khaybar. In addition to them, Abu Hurayrah (radi Allahu anhu) was also given a share, as will be clarified in the following narration.

Benefits and Issues:
This gift was given from the khums (one-fifth share of war booty).
Over which the Prophet sallallahu alayhi wa sallam himself had authority.
Or, with the consent of the other warriors, it was given from the spoils of war in order to console these emigrants.
And Allah knows best. (Khatabi)