What about polygamy?

Why were multiple wives or concubines allowed in the Old Testament?

Genesis 2:23-24, as Christ pointed out, teaches monogamy as God’s will for man. Now there is no possibility of a husband’s constituting a unity with one wife if he also has another wife–or several others. This is made very clear by the analogy in Ephesians 5:23. The implication here is that there is but one true church and that it stands in a relationship to the heavenly Bridegroom like that of the wife toward her husband. Christ is not the Head of many different churches; He has but a single mystical body–not several different bodies–and therefore His one and only church is viewed as the antitype of monogamous marriage. Polygamy is absolutely excluded. As we examine the scriptural record, we come to the realization that every case of polygamy or concubinage amounted to a failure to follow God’s original model and plan. The fact of the matter was that while polygamy was contrary to God’s intention and ideal, nevertheless, because of what Christ called “the hardness of men’s hearts” (Matthew 19:8), it was tolerated–especially in the case of a political leader whose dynasty would fail if he produced no son by his first wife.

–The Encyclopedia of Bible Difficulties

Why did God command Abraham to be circumcised?

Why did God command Abraham, and those men who followed, to be circumcised (Genesis 17:10)?

Circumcision was usually practiced in the ancient world as a rite of passage into puberty or marriage, though it does not seem to have been practiced among the Canaanites. God, however, gave this peculiar custom new meaning when he required it of Abraham. For Abraham, circumcision was a mark of possession, indicating that he belonged to God. It was also a sign of commitment, symbolizing that the Lord alone would be the one he would trust and serve. Some think it indicated a type of oath: “May I be cut off from my people as my foreskin has been cut off, if I am not faithful to the Lord (Gen. 17:14).

In many ways, God’s relationship with Abraham, as symbolized by circumcision, is similar to that of a marriage covenant. The commitment that God intends a husband and a wife to have for each other illustrates the commitment that God wanted from Abraham. Throughout the Old Testament, God characterizes himself as a husband to his people, and adultery is used as a metaphor for their idolatry and unfaithfulness to him (see, for example, Hosea 2:16; 4:15).

–The Quest Study Bible

Jacob Blessed for Deceiving?

Why was Jacob blessed even though he deceived his father to receive the blessing (Genesis 27:5ff.)?

First, a comment about the rite of blessing. Our culture affirms equality and even distribution, which make Isaac’s response difficult to understand. But in that culture only one son could inherit the family blessing. In this case only one son could provide the family line through which the Messiah would come.

Why would God bless a deceitful person? Obviously not because the person was deceitful. For a reason known only to God, he chose to bless Jacob and not Esau. Paul points out that since his choice was made before they were even born, it was not based on their merit (Romans 9:10-13) but on God’s sovereign freedom. God’s grace and blessing are always undeserved and unexpected.

–The Quest Study Bible

How did Zipporah Save Moses' Life?

Exodus 4:24-26 (NIV)

²⁴At a lodging place on the way, the LORD met Moses and was about to kill him. ²⁵But Zipporah took a flint knife, cut off her son's foreskin and touched Moses' feet with it. "Surely you are a bridegroom of blood to me," she said. ²⁶So the LORD let him alone. (At that time she said "bridegroom of blood," referring to circumcision.)

This event happens right before Moses goes to Pharaoh to deliver the Israelites from Egypt. This account of Zipporah circumcising her son, touching Moses' feet with the foreskin, and then calling Moses a "bridegroom of blood" seems very odd. On top of that, we read that God was about to kill Moses and the actions of his quick-thinking wife saved his life. This also seems out of place.

There is a fair amount of consensus among Old Testament scholars that this is a story about the profound importance of circumcision in the covenant. Circumcision was a kind of signature on the part of a person, which meant they wanted to be in a covenant relationship with God. Apparently Moses had not circumcised his son, although he knew he should have. Most likely, he has not been circumcised himself, which means he is deliberately disobeying God. He is holding himself outside of a covenant relationship with the Lord. There is simply no way he can take on God's mission until this is remedied.

So Zipporah, his wife, recognizing what's happening, takes a flint knife--the appropriate instrument--and circumcises their son. Then she touches Moses' feet. The word for feet is often a euphemism in Semitic culture for genitals. She touches him as a kind of temporary, vicarious circumcision of Moses until the time comes when Moses can be properly circumcised.

When Zipporah makes that statement about "you're a bridegroom of blood to me, " it might sound like a negative thing to say, like, "What a lot of bloodshed you and your God are causing me." But this is not what she is saying. It was actually a ritual marriage statement that a Hebrew bride would make when her groom had been circumcised before marriage. It's a positive statement: "You are blood kin to me. We're members of one family. We're a covenant people together." What's really happening here is that Moses has been disobedient to God's covenant calling. God is serious about it, and Zipporah's quick insight and actions save Moses' life!

-John Ortberg