Ali is Seal of Legatees. Abbas is Seal of Emigrants

 بِسۡمِ اللّٰہِ الرَّحۡمٰنِ الرَّحِیۡمِ

والصلاة والسلام على خاتم النبيين

اَلۡحَمۡدُ لِلّٰہِ رَبِّ الۡعٰلَمِیۡنَ

An indication as to the accurate meaning of the term خاتم النبيين Seal of the Prophets can be found in certain statements attributed to the most holy Prophet Muhammad صلى الله عليه وسلم in which he applies the word خاتم seal to some of his own relatives, namely, his son-in-law Ali and his youngest paternal uncle Abbas رضى الله عنهما

Ibn Hajr al-Asqalani brings forth a marfu report in which Abu Dharr al-Ghifari رضى الله عنه narrates that the Prophet صلى الله عليه وسلم said:

أَنَا خَاتَمُ النَّبِيِّينَ وَعَلِيٌّ ‌خَاتَمُ ‌الْأَوْصِيَاءِ

I am Seal of the Prophets and Ali is Seal of the Legatees

(Fath al-Bari; v.8, p.150)

Although the authenticity of this narration is not established as per my research, there is a sound narration in which the Prophet’s grandson Hasan رضى الله عنه reportedly declared his martyred father Ali خاتم الاوصياء Seal of the Legatees:

حَدَّثَنَا أَحْمَدُ بْنُ زُهَيْرٍ قَالَ نا أَحْمَدُ بْنُ يَحْيَى الصُّوفِيُّ قَالَ نا إِسْمَاعِيلُ بْنُ أَبَانَ الْوَرَّاقُ قَالَ نا سَلَّامُ بْنُ أَبِي عَمْرَةَ عَنْ مَعْرُوفِ بْنِ خَرَّبُوذَ عَنْ أَبِي الطُّفَيْلِ قَالَ خَطَبَ الْحَسَنُ بْنُ عَلِيِّ بْنِ أَبِي طَالِبٍ فَحَمِدَ اللَّهَ وَأَثْنَى عَلَيْهِ وَذَكَرَ أَمِيرُ الْمُؤْمِنِينَ عَلِيًّا رَضِي اللَّهُ عَنْهُ ‌خَاتَمَ ‌الْأَوْصِيَاءِ وَوَصِيَّ خَاتَمِ الْأَنْبِيَاءِ وَأَمِينَ الصِّدِّيقِينَ وَالشُّهَدَاءِ

Abu Tufail [Amir bin Wathila al-Laythi] رضى الله عنه said: Hasan bin Ali bin Abi Talib gave a sermon, praising Allah, and mentioned amir al-Mu’minin Ali رضى الله عنه Seal of the Legatees, and legatee of the Seal of the Prophets, and the trustworthy of the Truthful and the Martyrs (Mu’jam al-Awsat lil-Tabarani; v.2, p.336, #2155)

Now if Seal of the Prophets is interpreted to mean that he is literally the last of the Prophets then logically Seal of the Legatees must mean that sayyidina Ali كرم الله وجهه is literally the last of the legatees, an absurd notion.

Regarding his beloved paternal uncle Abbas bin Abd al-Muttalib رضى الله عنه the Prophet صلى الله عليه وسلم reportedly said:

يَا عَمِّ اطْمَئِنَّ فَإِنَّكَ ‌خَاتَمُ ‌الْمُهَاجِرِينَ فِي الْهِجْرَةِ كَمَا أَنَا خَاتَمُ النَّبِيِّينَ فِي النُّبُوَّةِ

O uncle, rest assured, for you are the Seal of Emigrants in emigration as I am the Seal of Prophets in prophesy

اجْلِسْ يَا عَمِّ، فَأَنْتَ ‌خَاتَمُ ‌الْمُهَاجِرِينَ كَمَا أَنَا خَاتَمُ النَّبِيِّينَ

Sit, O uncle, for you are the Seal of Emigrants as I am the Seal of Prophets

(Fada’il us-Sahabah li-Ahmad bin Hanbal; v.2, pp.941-942, #1812, 1813)

Here some have argued that the Prophet’s uncle Abbas رضى الله عنه was literally the last of the Believers to make the hijra or emigration from Mecca to Medina, and this strengthens the interpretation of خاتم النبيين to mean last of the Prophets literally. However, they miss the fact that sayyidina Abbas رضى الله عنه is not the last emigrant in absolute or unqualified terms, as the phenomenon of hijra/emigration, even as a religious expression, continues till this day. The Prophet صلى الله عليه وسلم even said:

سَتَكُونُ هِجْرَةٌ بَعْدَ هِجْرَةٍ فَخِيَارُ أَهْلِ الأَرْضِ أَلْزَمُهُمْ مُهَاجَرَ إِبْرَاهِيمَ

عنقریب ہجرت کے بعد ہجرت ہو گی تو زمین والوں میں بہتر وہ لوگ ہوں گے جو ابراہیم علیہ السلام کی ہجرت گاہ کو لازم پکڑیں گے

There shall be an emigration after emigration, and the best people of Earth are those most adherent to the emigration of Abraham

(Sunan Abi Dawud, #2482)

لاَ تَنْقَطِعُ الْهِجْرَةُ حَتَّى تَنْقَطِعَ التَّوْبَةُ وَلاَ تَنْقَطِعُ التَّوْبَةُ حَتَّى تَطْلُعَ الشَّمْسُ مِنْ مَغْرِبِهَا

ہجرت ختم نہیں ہو گی یہاں تک کہ توبہ کا سلسلہ ختم ہو جائے ، اور توبہ ختم نہیں ہو گی یہاں تک کہ سورج پچھم سے نکل آئے

Emigration will not end until repentance ends, and repentance will not end until the sun rises from the west

(Sunan Abi Dawud, #2479)

In these narrations the Prophet صلى الله عليه وسلم has declared as continuous both a general hijra and a particular hijra which is the emigration of Believers to the Holy Land.