SB 6.1.10

kvacin nivartate ’bhadrāt
 kvacic carati tat punaḥ
prāyaścittam atho ’pārthaṁ
 manye kuñjara-śaucavat
Synonyms: 
kvacit — sometimes; nivartate — ceases; abhadrāt — from sinful activity; kvacit — sometimes; carati — commits; tat — that (sinful activity); punaḥ — again; prāyaścittam — the process of atonement; atho — therefore; apārtham — useless; manye — I consider; kuñjara-śaucavat — exactly like the bathing of an elephant.
Translation: 
Sometimes one who is very alert so as not to commit sinful acts is victimized by sinful life again. I therefore consider this process of repeated sinning and atoning to be useless. It is like the bathing of an elephant, for an elephant cleanses itself by taking a full bath, but then throws dust over its head and body as soon as it returns to the land.
Purport: 

When Parīkṣit Mahārāja inquired how a human being could free himself from sinful activities so as not to be forced to go to hellish planetary systems after death, Śukadeva Gosvāmī answered that the process of counteracting sinful life is atonement. In this way Śukadeva Gosvāmī tested the intelligence of Mahārāja Parīkṣit, who passed the examination by refusing to accept this process as genuine. Now Parīkṣit Mahārāja is expecting another answer from his spiritual master, Śukadeva Gosvāmī.