"Khabbab came to ʿUmar and said: 'Come close, for no one deserves this meeting more than you, except ʿAmmar.' Then Khabbab started to show him the marks on his back where the idolaters had tortured him."  

ادْنُ فَمَا أَحَدٌ أَحَقَّ بِهَذَا الْمَجْلِسِ مِنْكَ إِلاَّ عَمَّارٌ فَجَعَلَ خَبَّابٌ يُرِيهِ آثَارًا بِظَهْرِهِ مِمَّا عَذَّبَهُ الْمُشْرِكُونَ  

The Messenger of Allah said: The most merciful of my Ummah towards my Ummah is Abu Bakr; the one who adheres most sternly to the religion of Allah is 'Umar; the most sincere of them in shyness and modesty is 'Uthman; the best judge is 'Ali bin Abu Talib; the best in reciting the Book of Allah is Ubayy bin Ka'b; the most knowledgeable of what is lawful and unlawful is Mu'adh bin Jabal; and the most knowledgeable of the rules of inheritance (Fara'id) is Zaid bin Thabit. And every nation has a trustworthy guardian, and the trustworthy guardian of this Ummah is Abu 'Ubaidah bin Jarrah."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ أَرْحَمُ أُمَّتِي بِأُمَّتِي أَبُو بَكْرٍ وَأَشَدُّهُمْ فِي دِينِ اللَّهِ عُمَرُ وَأَصْدَقُهُمْ حَيَاءً عُثْمَانُ وَأَقْضَاهُمْ عَلِيُّ بْنُ أَبِي طَالِبٍ وَأَقْرَؤُهُمْ لِكِتَابِ اللَّهِ أُبَىُّ بْنُ كَعْبٍ وَأَعْلَمُهُمْ بِالْحَلاَلِ وَالْحَرَامِ مُعَاذُ بْنُ جَبَلٍ وَأَفْرَضُهُمْ زَيْدُ بْنُ ثَابِتٍ أَلاَ وَإِنَّ لِكُلِّ أُمَّةٍ أَمِينًا وَأَمِينُ هَذِهِ الأُمَّةِ أَبُو عُبَيْدَةَ بْنُ الْجَرَّاحِ  

Zaid was: "The most knowledgeable of them concerning the rules of inheritance."  

عَنْ أَبِي قِلاَبَةَ مثله عند إبن قدامة غير أنه يقول في حق زيد (وَأَعْلَمُهُمْ بِالْفَرَائِضِ)