Nahj al-Balāgha
Hadith 1293وَآمَرَهُ أَلَّا يَعْمَلَ بِشَيْءٍ مِنْ طَاعَةِ اللهِ فِيما ظَهَرَ فَيُخَالِفَ إِلَى غَيْرِهِ فِيَما أَسَرَّ، وَمَنْ لَمْ يَخْتَلِفْ سِرُّهُ وَعَلَانِيَتُهُ، وَفِعْلُهُ وَمَقَالَتُهُ، فَقَدْ أَدّى الْأَمَانَةَ، وَأَخْلَصَ الْعِبَادَةَ.
He also orders him that whatever he does in obedience to Allāh openly should not be different from what he does secretly. He whose hidden position is not different from his open position, and whose action is not different from his words, has discharged his obligation and his worship is pure.