remorse and repentance (tawbah)

فَبَعَثَ ٱللَّهُ غُرَابًا يَبْحَثُ فِى ٱلْأَرْضِ لِيُرِيَهُۥ كَيْفَ يُوَٰرِى سَوْءَةَ أَخِيهِ ۚ قَالَ يَـٰوَيْلَتَىٰٓ أَعَجَزْتُ أَنْ أَكُونَ مِثْلَ هَـٰذَا ٱلْغُرَابِ فَأُوَٰرِىَ سَوْءَةَ أَخِى ۖ فَأَصْبَحَ مِنَ ٱلنَّـٰدِمِينَ

Then Allāh sent a crow searching [i.e., scratching] in the ground to show him how to hide the disgrace of his brother. He said, "O woe to me! Have I failed to be like this crow and hide the disgrace [i.e., body] of my brother?" And he became of the regretful.