Sirach 9:8
Ben Sira, Ecclesiasticus3 Do not go near a loose woman, or you will fall into her snares. 4 Do not dally with a singing girl, or you will be caught by her tricks. 5 Do not look intently at a virgin, or you may stumble and incur penalties for her. 6 Do not give yourself to prostitutes, or you may lose your inheritance. 7 Do not look around in the streets of a city, or wander about in its deserted sections. 8 Turn away your eyes from a shapely woman, and do not gaze at beauty belonging to another; many have been seduced by a woman's beauty, and by it passion is kindled like a fire. 9 Never dine with another man's wife, or revel with her at wine; or your heart may turn aside to her, and in blood you may be plunged into destruction.
Matthew 5:28
27 “You have heard that it was said, ‘Do not commit adultery.’ 28 But I say to you that whoever looks at a woman to desire her has already committed adultery with her in his heart. 29 If your right eye causes you to sin, tear it out and throw it away! It is better to lose one of your members than to have your whole body thrown into hell. 30 If your right hand causes you to sin, cut it off and throw it away! It is better to lose one of your members than to have your whole body go into hell.
Notes and References
"... The sage begins by emphasizing respect for marriage. The young man is to avoid jealousy toward his wife, else she may be provoked to evil. In 9:2 Ben Sira displays his cautious outlook (33:20): giving power to a woman could enable her to disgrace her husband by trampling on his dignity (Proverbs 31:3). Moreover, the male student should avoid intimacy with a strange (or foreign) woman, who might catch him in her snares (Proverbs 7:23). Sirach 9:5 advises against lustful thoughts toward a virgin (Job 31:1; Matthew 5:28). Moreover, the student associating too closely with a married woman will go down in blood to the grave (Proverbs 2:18; 7:27), probably a reference to the death penalty stipulated for adulterers (Leviticus 20:10) or to the husband’s revenge (Proverbs 6:34) ..."
Durken, Daniel The New Collegeville Bible Commentary: In One Volume (p. 1238) Liturgical Press, 2017