"The fruit of the Spirit" in Galatians 5:22 appears to be a general allusion to Isaiah's promise that the Holy Spirit would bring about abundant fertility in the coming new age. Isaiah's repeated prophecies (especially Isaiah 32 and, above all, Isaiah 57) that in the new creation the Spirit would he the bearer of plentiful fruitfulness, are at the forefront of Paul's usage.
This article is the second in a trilogy discussing Galatians 5:22-23 and the fruit of the Spirit. The author explains that the fruit needs to be evident, such that our lives are consistent with our message, for the sake of integrity. He discusses what exactly is the fruit of the Spirit is, as both the product and proof of regeneration. Every individual in this life produces fruit, either good or bad.