Preventing Nocturnal Emissions through the Bedtime Shema

הלכות קריאת שמע על המטה א:א

(Painting by Miriam Gair)

One way the desire for sexual immorality overcomes a person is when he is sleeping, and Heaven forbid has a nocturnal emission.  Therefore, in order to prevent this from happening a person should nullify and blot out any inappropriate thoughts from his mind before going to sleep.  One great way to accomplish this is by reading the Bedtime Shema, which is a great rectification for such thoughts and possible occurrences.  This is because when one accepts upon himself the Yoke of Heaven just before going to sleep he separates his soul from the souls of the erev rav, and includes his soul within the 12 Tribes, which correspond to the Kingship of Holiness.  By doing this he distances himself from evil thoughts.  And, then as he is sleeping he will be able to acquire a new soul and new insights into the Torah.  This is the foundation of the entire blessing of HaMapil as well as all of the verses and confessions that we are accustomed to say in the Bedtime Shema.