Bhishma said O son, a Kshatriya is generally engaged in decds of fierceness. In his case, sacrifices and gifts, are considered as cleansing or sanctifying him.
भीष्म उवाच रौद्रं कर्म क्षत्रियस्य सततं तात वर्तते। तस्य वैतानिकं कर्म दानं चैवेह पावनम्॥