Srimad Bhagavatam Canto 06, Chapter 01, Text 62

SB 6.1.62

stambhayann atmanatmanam
 yavat sattvam yatha-srutam
na sasaka samadhatum
 mano madana-vepitam
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
As far as possible he patiently tried to remember the instructions of the sastras not even to see a woman. With the help of this knowledge and his intellect, he tried to control his lusty desires, but because of the force of Cupid within his heart, he failed to control his mind.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Unless one is very strong in knowledge, patience and proper bodily, mental and intellectual behavior, controlling one’s lusty desires is extremely difficult. Thus after seeing a man embracing a young woman and practically doing everything required for sex life, even a fully qualified brahmana, as described above, could not control his lusty desires and restrain himself from pursuing them. Because of the force of materialistic life, to maintain self-control is extremely difficult unless one is specifically under the protection of the Supreme Personality of Godhead through devotional service.
Srimad Bhagavatam Canto 06, Chapter 01, Text 61
Srimad Bhagavatam Canto 06, Chapter 01, Text 63