Śatapatha Brāhmaṇa ("of a hundred paths") 1.3.5.13

1.3.5.13

trireva prathamāṃ triruttamāmanavānannanubrūyāt | trayo vā ime lokāstadimānevaitallokāṃtsaṃtanotīmāṃllokāṃtspṛṇute traya ime puruṣe prāṇā etamevāsminnetatsaṃtatamavyavacinnaṃ dadhātyetadanuvacanam

Thrice he should recite the first and thrice the last (verse), without drawing breath; for three are these worlds, so that he thereby spreads (san-tan) these worlds, gains these worlds. Also three breaths there are in man: this recitation thereby causes him (the sacrificer) to be extended (santata), not cut short (by death).