Sunan Ibn Majah, Book 1, Hadith 257 (In-Book) ⓘ
It was narrated that Abu Harun Al-'Abdi said: "When we came to Abu Sa'eed Al-Khudri, he would say: 'Welcome, in accordance with the injunction of the Messenger of Allah, for the Messenger of Allah said to us: "The people will follow you; they will come to you from all parts of the earth seeking to understand the religion. So when they come to you, take care of them."
حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا عَمْرُو بْنُ مُحَمَّدٍ الْعَنْقَزِيُّ، أَنْبَأَنَا سُفْيَانُ، عَنْ أَبِي هَارُونَ الْعَبْدِيِّ، قَالَ كُنَّا إِذَا أَتَيْنَا أَبَا سَعِيدٍ الْخُدْرِيَّ قَالَ مَرْحَبًا بِوَصِيَّةِ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ . إِنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ لَنَا " إِنَّ النَّاسَ لَكُمْ تَبَعٌ وَإِنَّهُمْ سَيَأْتُونَكُمْ مِنْ أَقْطَارِ الأَرْضِ يَتَفَقَّهُونَ فِي الدِّينِ فَإِذَا جَاءُوكُمْ فَاسْتَوْصُوا بِهِمْ خَيْرًا " .
also referenced under: Hadith 249 (Reference) & Volume 1, Book 1, Hadith 249 (DarusSalam)