My dear great and powerful Lord Śiva, you were created first from the mouth of Lord Brahmā in order to protect the brāhmaṇas in pursuing education, austerities, vows and self-realization. As protector of the brāhmaṇas, you always protect the regulative principles they follow, just as a cowherd boy keeps a stick in his hand to give protection to the cows.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
विद्यातपोव्रतधरान् मुखतः स्म विप्रान् ब्रह्मात्मतत्त्वमवितुं प्रथमं त्वमस्राक् । तद्ब्राह्मणान् परम सर्वविपत्सु पासि पालः पशूनिव विभो प्रगृहीतदण्डः
vidyātapovratadharān mukhataḥ sma viprān brahmātmatattvamavituṃ prathamaṃ tvamasrāk | tadbrāhmaṇān parama sarvavipatsu pāsi pālaḥ paśūniva vibho pragṛhītadaṇḍaḥ
SB 4.7.14