SB 3.12.18
tapa atistha bhadram te
sarva-bhuta-sukhavaham
tapasaiva yatha purvam
srasta visvam idam bhavan
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
My dear son, you had better situate yourself in penance, which is auspicious for all living entities and which will bring all benediction upon you. By penance only shall you be able to create the universe as it was before.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In the creation, maintenance and dissolution of the cosmic manifestation, the three deities Brahma, Visnu and Mahesvara, or Siva, are respectively in charge. Rudra was advised not to destroy while the period of creation and maintenance was going on, but to situate himself in penance and wait for the time of dissolution, when his services would be called for.