عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ رَضِيَ اللَّهُ عَنْهُ عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَ لَوْ أَنَّ أَحَدَكُمْ يَعْمَلُ فِي صَخْرَةٍ صَمَّاءَ لَيْسَ لَهَا بَابٌ وَلَا كُوَّةٌ لَخَرَجَ عَمَلُهُ لِلنَّاسِ كَائِنًا مَا كَانَ
Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: If a person performs a deed inside a solid rock, which has neither a door nor a window, even then his deed will come out for the people, whatever kind it may be.