Bhagvat Puran Skandh 4 Adhyay 19

After seeing that the people under his rule are well settled, Maharaj Pruthu focuses on his spiritual self and decides to carry out 100 Ashwamedh Yagya. Bitten by jealousy, the mercurial God, Indra feels that Pruthu will gain even more of a status than him by completing the 100 yagyas. Hence, he tries to disrupt the process disguising himself in different identities. The son of Pruthu, stops Indra from his mischief. Knowing what Indra is trying to do, Pruthu gets angrier and gets ready to kill Indra. However, Brahamaji appears and requests Pruthu to disengage and avoid taking part in such misdeed. Pruthu, in his maturity, lets go of Indra and forgives him.