Bilal on Hypocrisy: Do not show people two faces with an evil heart

Ibn Abi Dunya reported: Bilal ibn Sa’d, may Allah have mercy on him, said, “Do not be one with two faces and two tongues, making a show for people to praise you while your heart is wicked.”

Source: al-Ikhlāṣ li Ibn Abī Dunyā 28

عن ابن أبي الدنيا قال بلال بن سعد رحمه الله لَا تَكُنْ ذَا وَجْهَيْنِ وَذَا لِسَانَيْنِ تُظْهِرُ لِلنَّاسِ لِيَحْمَدُوكَ وَقَلْبُكَ فَاجِرٌ

28 الإخلاص والنية لابن أبي الدنيا