Śatapatha Brāhmaṇa ("of a hundred paths") 13.8.2.6

13.8.2.6

ṣaṅgavam bhavati ṣaḍṛtavaḥ samvatsara ṛtuṣvevainametatsamvatvare pratiṣṭhāyām pratiṣṭhāpayati tadapasalavi paryāhṛtyottarataḥ pratīcīm prathamāṃ sītām kṛṣati vāyuḥ punātviti jaghanārdhena dakṣiṇāgnerbhrājaseti dakṣiṇārdhena prācīṃ sūryasya varcasetyagreṇodīcīm

It is (a team) of six oxen,--six seasons are a year: on the seasons, on the year, as a firm foundation, he thus establishes him. Having turned round (the plough) from right to left, he ploughs the first furrow with (Vâg. S. XXXV, 3), 'May Vâyu purify!' along the north side (along the cord) towards the west; with, 'May Savitri purify!' along the west side towards the south; with, 'With Agni's lustre!' along the south side towards the east; with, 'With Sûrya's brilliance!' along the front side towards the north.