The Book of Faith
1/21. Chapter:
People excel over one another in faith, and the superiority of the people of Yemen in faith
Sahih Muslim
وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَزُهَيْرُ بْنُ حَرْبٍ، قَالاَ حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، بِهَذَا الإِسْنَادِ وَلَمْ يَذْكُرْ " رَأْسُ الْكُفْرِ قِبَلَ الْمَشْرِقِ " .
Qutaiba b. Sa'id and Zubair b. Harb say: Jarir narrated this on the authority of A'mash with the same chain of narrators (as mentioned above).
Reference : Sahih Muslim 52jIn-book reference : Book 1, Hadith 98USC-MSA web (English) reference : Book 1, Hadith 93