The Supreme Personality of Godhead is the creator of the material world. There are three processes in creationnamely creation, maintenance and finally annihilation. During the period of annihilation, at the end of each millennium, the Lord becomes angry, and the part of anger is played by Lord Siva, who is therefore called Rudra. When the Lord appeared in great anger to kill Hiranyakasipu, everyone was extremely afraid of the Lords attitude, but Lord Siva, knowing very well that the Lords anger is also His lila, was not afraid. Lord Siva knew that he would have to play the part of anger for the Lord. Kala means Lord Siva (Bhairava), and kopa refers to the Lords anger. These words, combined together as kopa-kala, refer to the end of each millennium. Actually the Lord is always affectionate toward His devotees, even though He may appear very angry. Because He is avyayatmabecause He never falls downeven when angry the Lord is affectionate toward His devotees. Therefore Lord Siva reminded the Lord to act like an affectionate father toward Prahlada Maharaja, who was standing by the Lords side as an exalted, fully surrendered devotee.