SB 4.19.23
yani rupani jagrhe
indro haya-jihirsaya
tani papasya khandani
lingam khandam ihocyate
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Whatever different forms Indra assumed as a mendicant because of his desire to seize the horse were symbols of atheistic philosophy.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
According to Vedic civilization, sannyasa is one of the essential items in the program of the varnasrama institution. One should accept sannyasa according to the parampara system of the acaryas. At the present moment, however, many so-called sannyasis or mendicants have no understanding of God consciousness. Such sannyasa was introduced by Indra because of his jealousy of Maharaja Prthu, and what he introduced is again appearing in the Age of Kali. Practically none of the sannyasis in this age are bona fide. No one can introduce any new system into the Vedic way of life; if one does so out of malice, he is to be known as a pasandi, or atheist. In the Vaisnava Tantra it is said:
yas tu narayanam devam
brahma-rudradi-daivataih
samatvenaiva vikseta
sa pasandi bhaved dhruvam
Although it is forbidden, there are many pasandis who coin terms like daridra-narayana and svami-narayana, although not even such demigods as Brahma and Siva can be equal to Narayana.