Be contrite (6)
I believe the answer is:
repent
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">be contrite</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for repent that I've seen before include "John the Baptist's cry" , "Express remorse for sin" , "Show remorse" , "lying on the ground" , "Turn away from sin" .)