First off,
One of the big issues is our modern definition of words and terms. For example, if I were to take another wife, and have kids with her, have I committed adultery according to our modern definition of the word? Of course, right? The problem with our modern definition is that the modern "Non-scriptural" definitions:
1.) Make Godly people ungodly ... when they aren't
2.) Make God inconsistent ... when He isn't
3.) Create commands that God says nothing at all about
4.) Alter commands that God gave, nullifying their meaning to make them fit our new, modern beliefs.
According to "our" modern definition, since David had 6 wives, and kids with 5 BEFORE he ever committed adultery, David committed adultery 5-6 times before God ever called him on it, and then didn't address his first 6 offences.
According to our modern definition, Solomon committed adultery about a thousand times, and yet, the scriptures are silent about it. You would think that Solomon would be the poster child for ungodly lust. Yet, God, and godly men and women, including Christ and the N.T. writers of scripture completely leave him out of all discussions of ungodly lust.
It gets even more interesting when we examine God's command about what to do when you take an additional wife, or the God's reproof of David for committing adultery with Bathsheba. It seems God even gave David the wives of his enemies, and would have been willing to give him even more if he would have avoided sinning.
It seems that most of us have a difference of opinion between the O.T. God's definition of a family, and our modern opinion. In the O.T. it was a man, all of his wives, and his kids with all of his wives. Adultery was only when an existing marriage relationship was broken to form another marriage relationship. Even in the N.T. this definition is consistent. The destruction of an existing marriage relationship to form another is considered adultery.
If we look at the passage about "adultery" in the heart, first thing we notice is that it is the word adultery, not the word fornication. Since Jesus was a Jew, and since His audience was all Jews at that time, we need to go with the definition for the word used: "Adultery", and not change it to the word "Fornication" because we wish to alter what was said and meant. Also, interestingly, the ONLY WORD AVAILABLE for married woman was used in this passage as well. From the context, we have the meaning, "If any man is in the presence of a woman married to another man, and dwells on her for the purpose of inflaming his lusts towards her, he has committed adultery with her in his heart." In order for this to occur, you couldn't draw a painting of her naked and be in the situation above. It requires the person to be in her presence. Also, it does not include those that are available to be married as they are not married yet.
That 1 Cor. 7 passage is an interesting one. Assuming that the people involved are both true Christians, if they are inflaming each others lusts, and the touching that is mentioned in 7:1 is occurring, and they are at risk of committing the fornication discussed in verse 2, and thus they are not able to control themselves, then, and only then, is it better to be married than single. Multiple times it states that if you can control your lusts, it is better not to get married. Yet, even if you are in this position, to avoid committing fornication (Illicit sexual intercourse) let them marry. The kicker ... even though things are getting out of hand ... or rather "into hand", if a pair of Christians gets married for this reason, and because they are at this point, the scriptures say that they have not sinned.
Remember David, and when He sinned. God calls EXACTLY what He says and means sin. Remember Solomon, and when God said he sinned. Again, God calls EXACTLY what is sin, sin. (The taking of foreign wives, or for us, marrying a non-Christian).
Lets assume that a Christian believes their spouse is a Christian, and yet their spouse departs from the faith they once professed. "They went out from us for they were never of us." or, if you prefer for those that refuse to listen to God and do not see His reproof, "Depart from Me ye who work iniquity for I NEVER knew you.". Is the Christian under slavery? Are they REQUIRED BY GOD to keep themselves bound to those who are non-Christians? Not according to scripture. They are free and not under bondage.
In the O.T. by the way, if you committed fornication by having sex with a woman (Not currently married to another man) you gained another wife, and did not have the ability to divorce her for the rest of your lives. God guards the sanctity of His definition of a family. Becoming one flesh completed that bond.
While we may seek to ignore a lot of the passages that pertain because we cannot "use" them to prove our beliefs true, or "use" them to prove all opposing beliefs false, and while we may seek to interpret all of our "selected" passages and facts in accordance with our beliefs, thus making God, and those He says are godly inconsistent, and even sinners though God says nothing, those that love truth do not do so. They interpret everything that is said, not said, done, and not done, in such a way that EVERYTHING fits perfectly with EVERYTHING else. To think that Solomon's sexual indulgence with a thousand women, not just looking at them naked, but actually having sex with them, is not an example of ungodly lust is a bit hard for many to believe. God's coming to him in a dream, and telling Solomon what HE was going to add to him for only wanting wisdom, clarifies where he got the heaps of horses (Largest stable complexes ever made by men), his heaps upon heaps of gold (Richest man that ever lived), and ... other things. If God does the heaping (Except for the foreign wives God did reprove him for) then did Solomon sin? No, right? Thus God is consistent... even when we do not like the conclusions we must make to see Him as such.
The question is, do we draw the lines, and the definitions, exactly where God draws them, or do we alter the meaning of words, terms, passages, what God and godly men and women say and do, and don't say and don't do to force everything to align with our beliefs? That which we love least will be forced to conform to that which we love most. Everyone either loves their beliefs more, or the truth of ALL that the word of God says and means more. That which we habitually do with the word of God proves which it is that we really love.
