Ṛgvidhāna · Chapter 3.37

na.ced.budhyeta.kiṃca.anyan.na.paśyec.śṛṇuyān.na.ca./
na.manasyed.yadā.yogam.tadā.prāptaḥ.sa.ucyate.//

hṛdyam.etam.ṛṣim.abhyasyet.paśyann.iva.yathā.śruti./
prāṇān.āyamya.ca.āsīno.yāvat.tam.cintayed.ṛṣim.//

ucchvasiṣyann.adho.nābhi.gamayitvā.manas.tathā./
ucchvased.evam.asakṛt.tanmanā.yogam.unnayet.//

evam.hi.yuñjant.sāmānyam.na.paśyet.śṛṇuyān.na.ca./
tadā.śanair.nayec.ceto.hṛdayād.ūrdhvam.eva.tu.//

samau.tu.jatrū.ca.āsyam.ca.nāsikā.nayane.bhruvau./
bhruvor.madhye.param.sthānam.tatra.etad.dhārayet.sthiram.//