Srimad Bhagavatam Canto 11, Chapter 16, Text 43

SB 11.16.43

yo vai van-manasi samyag
 asamyacchan dhiya yatih
tasya vratam tapo danam
 sravaty ama-ghatambu-vat
 
Translation: 
 
A transcendentalist who does not completely control his words and mind by superior intelligence will find that his spiritual vows, austerities and charity flow away just as water flows out of an unbaked clay pot.
 
Purport: 
 
When a clay pot is properly baked it holds any liquid substance without leakage. If a clay pot is not properly baked, however, water or any other liquid within it will seep out and be lost. Similarly, a transcendentalist who does not control his speech and mind will find that his spiritual discipline and austerity gradually seep away and are lost. Dana, or “charity,” refers to work performed for the welfare of others. Those who are trying to give the highest charity by preaching Krsna consciousness should not engage in speaking cleverly for the satisfaction of beautiful women, nor should they attempt to become artificially intellectual simply for the sake of mundane academic prestige. One should not even think of intimate sexual relationships, nor should one daydream of acquiring a prestigious position. Otherwise, one’s determination to strictly practice Krsna consciousness will be lost, as described here. One must control the mind, senses and speech by higher intelligence so that one’s life will be successful.
Srimad Bhagavatam Canto 11, Chapter 16, Text 42
Srimad Bhagavatam Canto 11, Chapter 16, Text 44