The Law Code of Yājñavalkya 1.3.51

1.3.51

sa daivo vivāho yasmin yajñānuṣṭhāne vitate ṛtvije śaktyālaṃkṛtā kanyā dīyate | yatra punar gomithunam ādāya kanyā dīyate sa ārṣaḥ | prathamajo daivavivāhajaś caturdaśa punāti saptāvarān saptaparān | uttaraja ārṣavivāhajaḥ ṣaṭ punāti trīn pūrvān trīn parān || 1.59 ||

The Daiva marriage is that in which, while the performance of a sacrifice is in progress, the maiden, adorned according to one's means, is given to an officiating priest. But where the maiden is given upon receiving a pair of cattle, that is the Ārṣa. The first-born, born of the Daiva marriage, purifies fourteen: seven later and seven earlier. The latter-born, born of the Ārṣa marriage, purifies six: three earlier and three later. || 1.59