The worst of the people is a man who is double-faced; he presents one face to some and another to others.  

أَنَّ النَّبِيَّ ﷺ قَالَ مِنْ شَرِّ النَّاسِ ذُو الْوَجْهَيْنِ الَّذِي يَأْتِي هَؤُلاَءِ بِوَجْهٍ وَهَؤُلاَءِ بِوَجْهٍ  

The Prophet ﷺ said: He who is two-faced in this world will have two tongues of fire on the Day of Resurrection.  

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ كَانَ لَهُ وَجْهَانِ فِي الدُّنْيَا كَانَ لَهُ يَوْمَ الْقِيَامَةِ لِسَانَانِ مِنْ نَارٍ