The ablative infinitive — which, like the accusative, is made only from the root-noun and that in tu — is found especially with the prepositions ā́ until and purā́ before.

a. Thus, ā́ támitoḥ (TS. etc.) until exhaustion; purā́ vācáḥ právaditoḥ (TS.) before utterance of the voice. In the Brāhmaṇa language, this is the well-nigh exclusive construction of the ablative (it occurs also with prāk, arvāk, etc.); in the Veda, the latter is used also after ṛté without, and after several verbs, as trā and pā protect, yu separate, bhī, etc.

b. In a few instances, by an attraction similar to that illustrated above for the dative (982 a), a noun dependent on this infinitive is put in the ablative beside it: thus, purā vāgbhyaḥ sampravaditoḥ (PB.) before the utterance together of the voices; trā́dhvaṁ kartā́d avapádaḥ (RV.) save us from falling down into the pit; purā dakṣiṇābhyo netoḥ (Āpast.)before the gifts are taken away.