To save a man from impersonal calamity is the greatest service to humanity. According to Caitanya Mahaprabhu, the Lord is full in six opulences & the rascal impersonalists says that the Lord has no form & the most dangerous accusation for the Lord that He assumes a material form when he descends. The Impersonalist is of the opinion that the absolute has no form & He appears in a particular type of form according to the whim of nonsense; The impersonalist presents any form nonsensical by his imagination & worships it as God. This accusation of the Lord is the greatest offense of the nonsense impersonalist. Such offender can never realize the transcendental form of the Lord & the Lord puts such nonsense into more & more darkness so that the dangerous impersonalist can never know the Supreme Personality of Godhead.

From Srila Prabhupada’s letter to Gargamuni — 19 October, 1967