For example, 1 John will say that it is written so that the readers may know that they have eternal life.  Love is the standard by which he judges.  1 Peter, on the other hand, has little to say about love.  It points out instead that baptism enters us into salvation, not by a physical washing of course, but by the pledge of a good conscience toward God.  Acts presents a similar picture.  James, assuming that faith is what saves, points out that your faith isn't really faith unless it produces good works.  Jesus says something similar when he points out that a bad tree cannot produce good fruit.  Paul argues in Romans for a more strict faith based salvation saying that good works, while a reaction to salvation, are not the measure of it.  Moreover, 1 Corinthians gives a clear picture that once in the church, one's immorality can cause someone to functionally cease to be saved and thus require them to be put out of the church.

It's not cut and dry and there is no a = b formula that is going to help you grasp it.  I will confidently say however, that I believe that if you are saved then it will manifest itself in a very real way in your behavior.  That is not to say that to sin is to lose one's salvation.  1 John reminds us that if we confess our sins, God is faithful and will forgive us.  (That's the same 1 John who says that if you think you're in the light but do not love your brother than you're fooling yourself.)