Brihadaranyaka Upanishad 1.22

ते होचुः — क्वासावभूद्यो न इत्थमसक्तेति — अयमास्ये अन्तरिति — सोऽयास्य आङ्गिरसः प्राणो ह्यङ्गानां रसः ॥

te hochuh — kvav asav abhud yo na ittham asakteti — ayam asye antar iti — so'yasyaa angirasah — prano hy anganam rasah ||

They said: 'Where was he who thus rescued us?' He was within the mouth (asya). He is called Ayasya Angirasa — for he is the essence (rasa) of the limbs (anga).

उन्होंने पूछा: 'वह कहाँ था जिसने इस प्रकार हमारी रक्षा की?' वह यहाँ मुख के भीतर है — वह 'अयास्य आङ्गिरस' है — क्योंकि प्राण अंगों का रस है।