Hi fhansen,
The issue is always the heart of the believer. I certainly wouldn't encourage anyone to 'deliberately' sin and hope for forgiveness after the fact, but...
We do sin! It seems apparent that the Scriptures, by this particular passage of Paul's writing, allows that we can still sin after being born again. I don't mean 'can still' as in making a deliberate decision to sin, but just that we do still sin. Now, when I weigh Paul's words against the words of John that say no one who continues to sin has known the Lord, I am left with an understanding that John is talking about 'deliberate and conscienceless' sin. In other words, if we know Jesus, we cannot continue to sin without consciousness that we are sinning and just go on with our life the way we always have. I find myself often asking for my Father's forgiveness for some action or thought, that fairly quickly comes to me that such was a sin against God's commands.
To more specifically answer the OP, I would say that no, it is not right, but yes, it can/will be forgiven if the heart of the guilty one is right with his Creator. David lied after the Scriptures seem to clearly tell us that he was a man after God's own heart, and in the end, we are led to understand that David was still a righteous man as seen by God. Joshua encouraged Rahab to sin and tell the people looking for them that she hadn't seen them. Abraham lied at least twice about his relationship to Sarah, and yet, God constantly tells us that Abraham was a righteous man before God.
Finally, we have to assess Jesus' words in explaining the whole of the law in Israel. Jesus said that the number one most important law was to love God with everything that we are. The second, he said, was to treat others as we ourselves would want to be treated. So, if the person who hid the Jews loved God with all their being, wouldn't they also be keeping the second commandment. Surely, if the situation was reversed and the Germans were hunting for the one who hid the Jews and their capture would mean fairly certain death, wouldn't they want the Jews to do the same thing for them? So, in not being forthright with the Germans, were they not treating the Jews in the same way that they themselves would want to be treated under the same circumstance? Jesus said that by obeying these two laws that one would keep the whole of the law and the prophets.
Of course, there is, in this situation, personal gain for the one lying to the Germans. Even had they given up the Jews hiding in their home, the Germans would likely have drug them out also because they had participated in hiding them in the first place. The Germans of the Nazi era were a cold and murderous bunch of folk. The tales I've heard and the stories I've read allow that the liar would have been as much in danger as those they were hiding from retaliation for their actions.
Just curious what you would have done under the circumstances? Would you have just flat out refused to give refuge to the Jews? Or would you have given refuge, but if someone asked about them, just opened the door and said sure, let me show you where they are? Is that what you believe Rahab should have done? Just open the door to the searchers and said sure they're upstairs hiding, come with me.
God bless you.
In Christ, Ted