Muwatta Malik 1831

وَحَدَّثَنِي مَالِكٌ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ مِنْ شَرِّ النَّاسِ ذُو الْوَجْهَيْنِ الَّذِي يَأْتِي هَؤُلاَءِ بِوَجْهٍ وَهَؤُلاَءِ بِوَجْهٍ ‏"‏ ‏.‏

Malik related to me from Abu'z-Zinad from al-Araj from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, said, "One of the most evil of people is the two-faced person who shows one face to these people and another face to those people

Reference

Muwatta Malik 1831

In-book

Book 56, Hadith 21