Beware what we love in our hearts
Let thy fountain be blessed: and rejoice with the wife of thy youth. Let her be as the loving hind and pleasant roe; let her breasts satisfy thee at all times; and be thou ravished always with her love. -- Proverbs 5:18-19
In Deuteronomy 17:17, the Lord commands the nation of Israel that when they are given a king, he shall not multiply wives to himself. King Solomon is famous for violating this commandment in a flagrant way, but his father was also weak in this regard. When you look at King David's life, his adultery with Bathsheba should not be surprising. Here are some examples:
1 Samuel 18:27 -- Therefore David arose and went, he and his men, and slew of the Philistines two hundred men; and David brought their foreskins, and they gave them in full tale to the king, that he might be the king's son in law. And Saul gave him Michal his daughter to wife.
1 Samuel 25:42-43 -- And Abigail hasted, and arose and rode upon an ass, with five damsels of hers that went after her; and she went after the messengers of David, and became his wife. David also took Ahinoam of Jezreel; and they were also both of them his wives.
2 Samuel 3:1-5 -- Now there was long war between the house of Saul and the house of David: but David waxed stronger and stronger, and the house of Saul waxed weaker and weaker. And unto David were sons born in Hebron: and his firstborn was Amnon, of Ahinoam the Jezreelitess; And his second, Chileab, of Abigail the wife of Nabal the Carmelite; and the third, Absalom the son of Maacah the daughter of Talmai king of Geshur; And the fourth, Adonijah the son of Haggith; and the fifth, Shephatiah the son of Abital; And the sixth, Ithream, by Eglah David's wife. These were born to David in Hebron.
2 Samuel 5:13 -- And David took him more concubines and wives out of Jerusalem, after he was come from Hebron: and there were yet sons and daughters born to David.
David always had a wandering eye, and was not satisfied with only having one wife. Before Bathsheba, his actions were honorable even if he was disobedient. Even with Nabal's wife, David did not take her as his wife until after he died of natural causes. But we can see the pattern in David's life that his adultery with Bathsheba should not have been a surprise.
The creation ordinance (established in Genesis 2:24 and reinforced in Ephesians 5:31) was for a man to cleave to his wife, and the two (not three or more) shall become one flesh. Scripture establishes the standard for elders and deacons as being the husband of one wife in 1 Timothy chapter 3 and Titus chapter 1. Polygamy is a rebellion against this standard.
It's easy for us to be judgmental of King David, but we need to be wary of what we hold dear in our own lives. Even if that thing is not causing us to sin now, will it cause us to sin at some point in the future? Is there something in our life that we would not be willing to live without? Is there something in our life we want more and more of, even though we have enough? Are we willing to discipline our love of the things we hold dear and put them under the authority of Jesus Christ?
These are very serious questions we must answer if we are to truly serve Jesus Christ.