Section 79 I.P.C. runs thus:

79. Nothing is an offence which is done by any person who is justified by law, or who by reason of a mistake of fact and not by reason of a mistake of law in good faith, believes himself to be justified by law, in doing it.

Justified by law

If the performance of the act which constitutes the offence is justified by law, i.e. by some other provision, then Section 79 exonerates the doer because the act ceases to be an offence.

For instance, if a person got certified his movie through censor board, a board which is establish under an act, then that person cannot be accused of obscenity under section 292 of IPC or enraging the sentiment of people.

Justified by mistake of fact

Likewise, if the act was done by one “who by reason of a mistake of fact in good faith believes himself to be justified by law in doing it” then also, the exception operates and the bona fide belief, although mistaken, eliminates the culpability.

Essential

If the offender can irrefutably establish that

  • is actually justified by law in doing the act or, alternatively,
  • that he entertained a mistake of fact and in good faith believed that he was justified by law in committing the act,

then, the weapon of Section 79 demolishes the prosecution.

Meaning of Justification

“Justified” according to Black’s Legal Dictionary means:

“Done on adequate reasons sufficiently supported by credible evidence, when weighed by unprejudiced mind, guided by common sense and by correct rules of law.”

The Shorter Oxford English Dictionary assigns this meaning for “justification”. The showing in court that one had sufficient reason for doing that which i.e. is called to answer; the ground for such a plea.

Lexically, the sense is clear. An act is justified by law if it is warranted, validated and made blameless by law.

Jurisprudentially viewed, an act may be an offence, definitionally speaking but; a forbidden act may not spell inevitable guilt. the law itself declares that in certain special circumstances it is not to be regarded as an offence. The chapter on General Exceptions of IPC operates in this province. Section 79 makes an offence a non-offence. Only when the offending act is actually justified by law or is bona fide believed by mistake of fact to be so justified.

Reference

Raj Kapoor vs Laxman, AIR 1980 SC 605, 1980 CriLJ 436, (1980) 2 SCC 175, 1980 2 SCR 512, 1980