What is the purpose of coming back together sexually, according to Les?
The purpose is to prevent Satan from tempting either spouse through their incontinency, so neither partner is driven outside the marriage relationship. Sexual desire is powerful and God-given, but it must not be abused; coming back together guards the marriage against Satan's temptation.
Les explains that Paul says couples are not to defraud one another unless it is by consent. If they agree to abstain from the marriage relationship for a time, that is allowed, but it should not be prolonged. They are to come together again so Satan does not tempt one or the other for their incontinency, and specifically so neither is tempted to go outside the marriage relationship. Les notes that emotional stress or physical impairment can enter in, but all things being normal, the sex drive is powerful and God put it there for a purpose; it is not to be abused.
Defraud ye not one the other, except it be with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency.
More Questions
Why does Paul say couples should come together again rather than abstain?
The purpose of coming back together is so that Satan does not tempt one or the other spouse, because of their incontinency (lack of self-control), to go outside the marriage relationship.