Whether sins of commission and omission differ specifically?

❌ Objection 1 : It would seem that sins of commission and omission differ specifically. For "offense" and "sin" are condivided with one another (Eph. 2:1), where it is written: "When you were dead in your offenses and sins," which words a gloss explains, saying: "'Offenses,' by omitting to do what was commanded, and 'sins,' by doing what was forbidden." Whence it is evident that "offenses" here denotes sins of omission; while "sin" denotes sins of commission. Therefore they differ specifically, since they are contrasted with one another as different species.

❌ Objection 2 : Further, it is essential to sin to be against God's law, for this is part of its definition, as is clear from what has been said (Question [71], Article [6]). Now in God's law, the affirmative precepts, against which is the sin of omission, are different from the negative precepts, against which is the sin of omission. Therefore sins of omission and commission differ specifically.

❌ Objection 3 : Further, omission and commission differ as affirmation and negation. Now affirmation and negation cannot be in the same species, since negation has no species; for "there is neither species nor difference of non-being," as the Philosopher states (Phys. iv, text. 67). Therefore omission and commission cannot belong to the same species.