Time-bound particulars or Timeless principles? David's sin with Bathsheba

When considering the interpretation and application of a passage of Scripture, it is necessary to evaluate it regarding whether it is an example of time-bound particulars or timeless principles.  An example debated within the Bible itself as recorded in the book of Acts is whether or not new Gentile Christians ought to obey the commands in the Hebrew Scriptures (Old Testament) regarding circumcision.  In the end, first Paul, and then the Jerusalem council agree that while the command of circumcision is normative for the descendants of Abraham (Jews) for all time, the time-bound particulars of it do not apply in the same way to Gentile converts operating under the New Covenant.  While the principle of being a sacred people, called by God to be holy, still applies to the Church (and its new initiation rite, baptism), the expression of that principle given to God for Israel did not apply to the Church.
Consider the case of David's lustful adultery with Bathsheba which is recorded in 2 Samuel 11.  On the one hand, the time-bound particulars of the situation might seem vastly different than any modern situational equivalent: David was a Jew (Law of Moses), living in ancient Israel, where he was a king, and his society still tolerated (wrongly) polygamy.  Where is the connection to your average Christian married man of Gentile background (Law of Grace), living in modern America, where he is an average citizen of no real power/wealth?  And yet, one need not find superficial connections between David's circumstances and those of a modern married Christian man because the timeless principles upon which David's actions are judged are not bound by his circumstances.  When David saw Bathsheba, lusted after her, sought her ought, had sex with her, and then conspired to have her husband killed so that he could keep her for himself, he violated the 6th and 7th commandments, "You shall not murder", "You shall not commit adultery", as well as the 10th, "You shall not covet your neighbor's...wife" {Exodus 20: 13,14,17 the numbering of the commandments varies by tradition}  If a modern married Christian man were to meet a woman, lust after her, have sex with her, and then conspire to have his own wife and her husband killed so they could be together, he too would be violating these same commandments.  While David was King of Israel, his actions were the same as thousands of other men (and women) who have befouled the sacred marital bed by allowing lust to lead to adultery.  While the circumstances surrounding a modern day affair (far too polite a word for actions that both anger God and tear families apart) bear little resemblance to David's palace intrigue, one need not struggle to apply the moral lesson given by the prophet Nathan to David when he rebuked him, "Why did you despise the word of the LORD by doing what is evil in his eyes?" (1 Samuel 12:9)  Times may have changed, but lust is still lust, marital infidelity is still marital infidelity, and conspiracy to rid oneself of a rival is still murder. 
In the end, there are certain passages of Scripture, commands and rituals, which either no longer apply in the New Covenant to the Church, or no longer apply in a modern world with free democratic citizens; at least not in the same way that they applied to our ancestors in the faith.  On these occasions we must seek out the timeless principles upon which these passages rest and then consider how to apply those principles to our situation; a more difficult task.  However, this may not be necessary as often as we think, for human nature has not changed in the past few thousand years, God's nature, in particular his justice, holiness, and righteousness, have never changed.  The people of the Bible were people just like us, facing the same temptations and trials (even if in different packaging), and needing, just as we do, the grace of God to overcome them.