Punishment is the holy Vishnu. He is the powerful Narayana. And because he always puts on dreadful from, therefore he is called Mahapurusha.
दण्डो हि भगवान् विष्णुर्दण्डो नारायणः प्रभुः। शश्वद् रूपं महद् बिभ्रन्महान् पुरुष उच्यते॥