"God's Word does not change. God's world, however, changes in every generation. These changes, in addition to new findings by scholars and a new variety of challenges to the gospel message, call for the church in each generation to interpret and apply God's Word for God's people." The Editors of The New American Commentary: Proverbs, Ecclesiastes, Song of Songs
Similar things are said in N.T. Wright's foreword to "The King Jesus Gospel: The Original Good News Revisited."
Wright says that "[p]art of the genius of genuine Christianity is that each generation has to think it through afresh. Precisely because (so Christians believe) God wants every single Christian to grow up in understanding as well as trust, the Christian faith has never been something that one generation can sort out in such a way as to leave their successors with no work to do."
He continued: "Like a young man inheriting a vast fortune, such a legacy could just make you lazy. All you'd have to do would be to look up things in the book, or to remember how it was when your favourite pastor used to do it, and that would be it. No room for character. No room for full human maturity--never mind full Christian maturity."