The concept here is that in addition to making a journey down the right, the narrow path, we need to be productive. Jesus returns to this theme in several of his parables. He draws upon it in his teaching to the disciples found in John 15. And Paul uses it in his letter to the Galatians where he teaches about fruit bearing. Further, the first Psalm draws upon this same image.
The product is not uniform in these teachings–virtues, good works, and new believers–may be the referent from place to place. It seems to me that the common theme is that being a Christian is far more than escaping Hell.
Again, all too often we run into church members who declare that they “believe in Jesus” which they may do in an intellectual, or mental way. But there is precious little evidence of fruit production in any of the three ways mentioned above.
Productivity is pictured as the result of being saved, not a means for salvation. I am to do good works because I am a follower of the Christ who went about doing good. I am to witness to others because I love them and want them to have the joy which I have. I am to be a loving virtuous person because the Holy Spirit has produced these virtues in me.
Again, this is to be understood in light of the work of the cross. Jesus provided for our forgiveness, our salvation. Our joy and and gratitude motivates us to be productive in loving folk, in being good persons, and in sharing with others how one can have peace with God.