The evil deed to be punished the quickest is agression.
رسولُ اللَّهِ صلى اللَّه عليه وآله : إنَّ أعجَلَ الشَّرِّ عُقوبَةً البَغيُ . الكافي : 2 / 327 / 1 .
The Prophet (SAWA) said, 'The evil deed to be punished the quickest is agression.' al-Kafi, v. 2, p. 327, no. 1