codaneti ca kriyāyāḥ pravartakaṃ nivartakaṃ ca vākyam āhuḥ / tathā svargakāmo 'gniṣṭomena yajeneti pravartakam, na hiṃsyād bhūtānīti nivartakam /
And by "injunction" they mean sentences that either prompt action or restrain from action; thus "one desiring heaven should perform the Agniṣṭoma" is prompting, [while] "one should not harm beings" is restraining.