SB 6.18.26
asasanasya tasyedam
dhruvam unnaddha-cetasah
mada-sosaka indrasya
bhuyad yena suto hi me
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Diti thought: Indra considers his body eternal, and thus he has become unrestrained. I therefore wish to have a son who can remove Indra’s madness. Let me adopt some means to help me in this.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
One who is in the bodily conception of life is compared in the sastras to animals like cows and asses. Diti wanted to punish Indra, who had become like a lower animal.