Shiva Purana
गुह्याद्गुह्यतरं कृष्ण सर्वत्र परमेश्वरे ॥ शिवे भक्तिर्न संदेहस्तया भक्तो विमुच्यते ॥ ५४ ॥
O Kṛṣṇa, this is the secret of secrets in regard to the lord. There is no doubt that a devotee becomes liberated through devotion.
english translation
guhyAdguhyataraM kRSNa sarvatra paramezvare ॥ zive bhaktirna saMdehastayA bhakto vimucyate ॥ 54 ॥
hk transliteration by Sanscript