Therefore it is no great thing if his ministers also be transformed as the ministers of righteousness; whose end shall be according to their works.
No great thing - no difficult matter.
Righteousness - answering to "light" (2 Corinthians 11:14); the manifestation wherewith God reveals Himself in Christ (Matthew 6:33; Romans 1:17).
End - the test, is the end, which strips off every specious, form into which Satan's agents now 'transform' themselves (cf. Philippians 3:19; Philippians 3:21).
According to their works - not according to their pretensions.