In the First Century in Corinth, there were some false teachings (or possibly, false assumptions) that crept into the church. These teachings eventually led to bad relationships choices in the church, so it had to be addressed. Paul, the writer of 1 Corinthians, first talks about sex, since it was a question that the Corinthians asked. From there, he moves his way into talking about marriage.
As you read through 1 Corinthians 7, look for this theme: Marriage is more than loving one another; it is a partnership for the kingdom. Paul strongly believes that the only way to fulfill God's calling in your life is to either stay single or marry someone that can help you in that journey.
They believed that our spirit was good and our body was bad. This is not a Jewish or Christian teaching, but something that was popularized by the Gnostics.
If the body is bad, then sex is also bad.
For this reason, there were some people who began to abstain from sex in marriage relationships, and the one who did not have an outlet for their sexual desires found their fulfillment in pagan temples (where prostitution was an act of worship). Paul warns the Christians to not abstain from sex.
Widows and Widowers (vv.8-9):
In the First Century, Rome needed a way to increase their labor force. For this reason, the Caesars passed a law that required all people to be sexually active. One of the laws fined people for being celibate. If your spouse died, you were given a one year grace period.
This is why Paul gives them permission to stay single ("It is good to stay unmarried..."). He states that God is okay with people remaining single after the death of their spouse. However, he gives a caveat - if a widow or widower still has uncontrollable sexual urges, it is beneficial for that person to seek out another marriage relationship.
In Paul's eyes, getting remarried for sexual fulfillment has more benefits than a person who is always "burning" with passion, because this can lead to a strong pull from a pagan temple.
Christian Married Couple (vv.10-11):
As people who are called to be agents of restoration of relationships, a Christians ought to have healthy marriages. If the wife and husband are both seeking a self-sacrificial relationship, there should be no issues in that union.
Christian and Non-Christian Couple (vv.12-16):
If the couple is "unequally yoked," the Christian should live a life that would make the Non-Christian feel fortunate for being in a relationship with a Christian. The Christian's influence should be a blessing to the rest of his/her family.
If the Non-Christian wants a divorce, then the rules mission remains the same - Bless that person, even through the divorce.
In that culture, the husband received a dowry from the wife's family. If they divorce, the husband must return the dowry to the wife's family. Paul is urging the husband to let go of the relationship (as well as the huge fortune) for the sake of peace.
Paul's Illustrations (vv.17-24):
Paul uses two illustrations (circumcision and slavery) to make a theological point.
When Paul declared that God no longer requires men to be circumcised, Christians learned that our physical appearance did not matter to God. Therefore, the only reason why men would want to get circumcised or get uncircumcised (there was a surgery where they would reattach skin to the penis) was to appease their Greek friends. According to Paul, this is an example of your Greek friends being your Lord.
Slavery in the First Century was different from our ideas of slavery today. When one was a slave, he or she could save his/her money (they were paid to be slaves), pay off their master to gain freedom. Upon becoming free, the master would hire that former slave to become a partner of his business.
For poor people, it was a get-rich-tactic. People will willingly become a slave in hopes to get rich in a few years. To Paul, this is another example of submitting one's allegiance to someone other than Jesus.
He is reminding the Corinthians to make their decisions in marriage by not compromising their commitment to Jesus.
At the time of this writing, there was a massive famine. Paul knows the worry of the young unmarrieds. He says it is completely acceptable to make a decision to wed or not wed based on your concerns of the famine.
Paul also reminds them that this famine will end soon (vv.29,31 "time is short" and "this world in its present form is passing away").
Legitimate Reasons For Staying Single (vv.32-40):
If you put Christ first in your life, then the mission of Christ should be central to your life. For this reason, Paul believes that a good reason for staying single is the lack of ability to juggle your calling and your family.