Mahārāja Yudhiṣṭhira inquired: It is very wonderful that the demon Śiśupāla merged into the body of the Supreme Personality of Godhead even though extremely envious. This sāyujya-mukti is impossible to attain even for great transcendentalists. How then did the enemy of the Lord attain it?
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
एतद्वेदितुमिच्छामः सर्व एव वयं मुने । भगवन्निन्दया वेनो द्विजैस्तमसि पातितः
etadveditumicchāmaḥ sarva eva vayaṃ mune | bhagavannindayā veno dvijaistamasi pātitaḥ
SB 7.1.16