The Story of the Woman caught in adultery isn't supposed to be in the Gospel of John. Many Bibles point this out, some by putting brackets before and after the story. Scholars point out words like "scribes," "teacher" and "Mt. Of Olives," appear nowhere else in John, but do frequently in the other Gospels. In fact, some believe this was meant to be a part of Luke.
But the better question is, "Why did someone locate this story in John where they did?" If you read chapters 7 and the rest of 8 you notice the amount of conflict between Jesus and the religious leaders. This story, whether originally written by John or not, is meant to compare the grace of Jesus with others who show no grace.
More than a century ago a boy named Josip Broz was given the honor of serving at the altar of his Croatian church. When he handed the goblet of wine to the priest his hand slipped and the goblet fell crashing on the floor. The priest slapped the boy's face and said, "Don't ever come back here." He didn't. But years later he came to be known by a different name, Marshall Tito, the dictator who ruled Yugoslavia.
At about the same time in another part of the world a young boy was serving at his church, St. Mary's in Peoria, Illinois. He assisted a visiting bishop, and he also slipped and dropped the goblet of wine.
Same event, but different result. The bishop looked at the boy and said, "Don't worry. Some day you will be as I am."
And he did. He became Archbishop Fulton Sheen, a leader of the Catholic Church who gave hope to millions through his weekly television show, Life is Worth Living.
I guess you could say that futures are made or changed by the amount of grace we experience. So let's never discount the impact of Jesus' grace in our lives, and then, let's be grace givers.