Śatapatha Brāhmaṇa ("of a hundred paths") 5.4.3.20

5.4.3.20

athemām pratyavekṣamāṇo japati | pṛthivi mātarmā mā hiṃsīrmo ahaṃ tvāmiti varuṇāddha vā abhiṣiṣicānātpṛthivī bibhayāṃ cakāra mahadvā ayamabhūdyo 'bhyaṣeci yadvai māyaṃ nāvadṛṇīyāditi varuṇa u ha pṛthivyai bibhayāṃ cakāra yadvai meyaṃ nāvadhūnvīteti tadanayaivaitanmitradheyamakuruta na hi mātā putraṃ hinasti na putro mātaram

Looking down on this (earth) he then mutters, 'O mother Earth, injure me not, nor I thee!' For the Earth was once afraid of Varuna, when he had been consecrated, thinking, 'Something great surely has he become now that he has been consecrated: I fear lest he may rend me asunder!' And Varuna also was afraid of the Earth, thinking, 'I fear lest she may shake me off!' Hence by that (formula) he entered into a friendly relation with her; for a mother does not injure her son, nor does a son injure his mother.