Lord Viṣṇu, the Supersoul within the core of everyone’s heart, is the ultimate enemy of the asuras and is therefore known as asura-dviṭ. He is the leader of all the demigods because all the demigods, including Lord Śiva and Lord Brahmā, exist under His protection. The great saintly persons, sages and Vaiṣṇavas also depend upon Him. To persecute the Vaiṣṇavas, therefore, is the only way to kill Viṣṇu.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
स हि सर्वसुराध्यक्षो ह्यसुरद्विड्गुहाशयः । तन्मूला देवताः सर्वाः सेश्वराः सचतुर्मुखाः । अयं वै तद्वधोपायो यदृषीणां विहिंसनम्
sa hi sarvasurādhyakṣo hyasuradviḍguhāśayaḥ | tanmūlā devatāḥ sarvāḥ seśvarāḥ sacaturmukhāḥ | ayaṃ vai tadvadhopāyo yadṛṣīṇāṃ vihiṃsanam
SB 10.4.42