Śatapatha Brāhmaṇa ("of a hundred paths") 9.4.2.10

9.4.2.10

vātahomairyunakti | prāṇā vai vātahomāḥ prāṇairevainametadyunakti tribhiryunakti trayo vai prāṇāḥ prāṇa udāno vyānastairevainametadyunktyadho 'dho dhuramadho 'dho hi dhuraṃ yogyaṃ yuñjanti hastābhyāṃ hastābhyāṃ hi yogyaṃ yuñjanti viparikrāmaṃ viparikrāmaṃ hi yogyaṃ yuñjanti

He yokes it with the oblations of air,--the oblations of air are the vital airs it is thus with the vital airs he yokes it. With three (oblations) he yokes it,--there are three vital airs, the out-breathing, up-breathing, and through-breathing: it is with these he thus yokes it. Just below the shaft (he offers), for just below the shaft the horse is yoked;--with his hands, for by the hands the horse is yoked;--in moving round, for in moving round the horse is yoked.