מדרש על משלי 2:11

R. Chanina and R. Jonathan were on the road and came upon two thoroughfares, one leading to the gate of an idol and the other to the gate of prostitutes. Said one to his colleague: "Let us go on that road which leads to the idol (Ib. b) as the evil spirit of idolators is killed." Whereupon his colleague remarked: "On the contrary, let us go on to the other road which leads to the prostitute so that we can overcome our evil spirit, and be rewarded." When they arrived at the prostitutes, the latter ran away to their homes. And his colleague asked him: "Whence did you infer [that such would happen]?" And the reply was: "From the following passage (Pr. 2, 11) Discretion shall watch over thee, discernment shall guard thee."