So much difficulty in Bible study comes from knowing who is being addressed. It is a vital principle of Biblical interpretation to understand that all of the Bible is written FOR us, but not all of it is written TO us. That is to say, we grow from studying the whole council of God, but we must understand when something is written to us and when it is not. Obvious examples of this are Paul's request that Timothy bring his cloak and books (2 Timothy4:13). Or perhaps the reader of Haggai may think it is his specific command to rebuild the temple, if he doesn't realize that that direct application is meant for Israel alone. While these examples may seem comical to us, this is the way that much legalism, and error has slipped into many peoples faiths.
A keen example of this is the principle can be found in Matthew 6:14-15: "For if you forgive men their trespasses, your heavenly Father will also forgive you. But if you do not forgive men their trespasses, neither will your Father forgive your trespasses." This is a favorite verse in legalistic sermons the world over. It is so tempting to pull this verse out and say, "If YOU don't forgive, then brother, GOD WON'T FORGIVE YOU!" How the human machine loves guilt and law. Some interpreters have tried to relieve the tension by claiming that this is a different type of forgiveness than other places, but it doesn't ultimately matter. Jesus delivered the Sermon on the Mount to Jews living under the law, clearing up the centuries of tradition and man made rules that had built up on the Law Moses gave. This sermon was given under the law, to people who lived under the Law, directly applying this to ourselves is reading someone else's mail.
So, if that verse is not written to us, do we not need to forgive one another? Who would forgive someone without the threat of eternal damnation hanging over their head? The answer? People who have found their salvation and hope in the grace of God. Ephesians 4:31 was written to church age believers who were living under Grace: "And be kind to one another, tenderhearted, forgiving one another, even as God in Christ forgave you." Why do we forgive one another? Because we are so grateful and overflowing from the forgiveness that we have already received from God. Notice the enormous change from "do so you can be" to "be so you can do"? And that makes all of the difference.