Śatapatha Brāhmaṇa ("of a hundred paths") 7.2.4.5

7.2.4.5

sa vai kṛṣṭe ninayati | tasmātkṛṣṭāya varṣati sa yatkṛṣṭa eva ninayennākṛṣṭe kṛṣṭāyaiva varṣennākṛṣṭāyātha yadakṛṣṭa eva ninayenna kṛṣṭe kṛṣṭāyaiva varṣenna kṛṣṭāya kṛṣṭe cākṛṣṭe ca ninayati tasmātkṛṣṭāya cākṛṣṭāya ca varṣati

On the ploughed ground he pours (water), whence it rains for (the benefit of) the ploughed land. Now were he only to pour it on the ploughed ground, and not on the unploughed, it would only rain for the ploughed land, not for the unploughed. And were he only to pour it on the unploughed ground, and not on the ploughed, it would only rain for the unploughed land, and not for the ploughed. He pours it both on the ploughed, and the unploughed, ground; whence it rains both for the ploughed, and the unploughed, ground.