O twice-born sages, by serving those devotees who are completely freed from all vice, great service is done. By such service, one gains affinity for hearing the messages of Vāsudeva.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
शुश्रूषोः श्रद्दधानस्य वासुदेवकथारुचिः । स्यान्महत्सेवया विप्राः पुण्यतीर्थनिषेवणात्
śuśrūṣoḥ śraddadhānasya vāsudevakathāruciḥ | syānmahatsevayā viprāḥ puṇyatīrthaniṣevaṇāt
SB 1.2.16