The practices of the good, the Smritis and the Vedas, are the three marks of righteousness. Besides these, the learned have said that the object (of doing works) is the fourth mark.
भीष्म उवाच सदाचारः स्मृतिर्वेदास्त्रिविधं धर्मलक्षणम्। चतुर्थमर्थमित्याहुः कवयो धर्मलक्षणम्॥