In the New Testament, fruit is used to symbolize the inevitable consequences of human choice. The outcome of any set of actions reflects favorably or unfavorably on the person who engages in them. As the Lord put it, “Each tree is known by its own fruit.” You do not find figs growing on thorn bushes or grapes among brambles.
The production of fruit is usually a positive thing, but fruit may be either good or bad. In Matthew’s gospel, the Lord tells his disciples false prophets may be recognized by the fruit they produce, which is diseased rather than healthy.
In Amos too, the image of fruit has to do with outcomes.