Hadith 16:48
Mahmud bin Labid (RAA) narrated that the Messenger of Allah (ﷺ) said:
“The thing I fear most for you is the lesser shirk (polytheism), showing-off (of good deeds).” Related by Ahmad with a good chain of narrators,
وَعَنْ مَحْمُودِ بْنِ لَبِيدٍ - رضى الله عنه - قَالَ: قَالَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -{ إِنَّ أَخْوَفَ مَا أَخَافُ عَلَيْكُمْ اَلشِّرْكُ اَلْأَصْغَرُ: اَلرِّيَاءُ } أَخْرَجَهُ أَحْمَدُ بِسَنَدٍ حَسَنٍ