What does Luke 6:44 mean?
Jesus continues with His metaphor of good and bad fruit and how they are produced. "Fruit" is the result of something. In the context of the Sermon on the Plain, the type of person symbolized by a good tree will follow Jesus and, when persecuted, love and forgive their oppressors. The person characterized by the bad tree will oppress those who follow Jesus and be quick to judge and condemn others. We need to judge our own fruit and make sure it is consistent with Christ before we can lead others (Luke 6:40–42).The implication of "gathered" figs and "picked" grapes is that the "fruit" is already harvested. We are looking down at it, determining where it was found. Jesus is saying that if we produce good fruit, like love, kindness, and self-control (Galatians 5:19–23), our hearts are probably good (Luke 6:45). If we produce bad fruit, like sexual immorality, anger, and division, we know we need to examine our hearts.
The mention of grapes evokes a point Jesus will not make until the Last Supper. He will tell the Twelve, "I am the vine; you are the branches. Whoever abides in me and I in him, he it is that bears much fruit, for apart from me you can do nothing" (John 15:5). We can only produce good fruit if we are connected to and nourished by Jesus through the Holy Spirit (Luke 6:40).
Matthew 7:15–20 uses the same analogy to warn against false prophets. In Matthew 12:33, Jesus uses the comparison as a condemnation of the Pharisees and scribes who claim His power comes from Satan (Matthew 12:22–37).