what does the bible say?
Matthew 7:16 uses the metaphor of bearing fruit to convey the good deeds that should be an outgrowth of faith. Fruit is used in this sense throughout the Bible. The Lord reads hearts (1 Samuel 16:7; Jeremiah 17:10), but people cannot, so deeds become evidence for what is in the heart. The Bible teaches that our deeds show our love for the Lord (Psalm 92:12–14; Matthew 7:16) and love for our neighbor (James 2:14–17; 1 John 3:16–18; 4:7–12). People can also bear bad fruit, their deeds revealing their unrighteous hearts. For example, when the Pharisees and Sadducees came to John the Baptist, he called them a "brood of vipers" and told them to "bear fruit in keeping with repentance" (Matthew 3:7–10). They were not to assume they were righteous because of their heritage or through ritual. They needed to be righteous in heart, which would be shown through their deeds. Jesus spoke a similar warning, saying, "How can you speak good, when you are evil? For out of the abundance of the heart the mouth speaks" (Matthew 12:34; cf. Luke 6:43–45). Here and many other parts of the Bible teach that our actions are the outflow of the heart (Galatians 5:22–23). Our deeds demonstrate the truth of our words and our hearts.