SB 6.18.56
matr-svasur abhiprayam
indra ajñaya manada
susrusanenasrama-stham
ditim paryacarat kavih
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O King, who are respectful to everyone, Indra understood Diti’s purpose, and thus he contrived to fulfill his own interests. Following the logic that self-preservation is the first law of nature, he wanted to break Diti’s promise. Thus he engaged himself in the service of Diti, his aunt, who was residing in an asrama.