Read: Luke 6:42-45
After telling a parable concerning teachers, Jesus gives another parable talking about one’s deeds and speech. He illustrates how deeds and speech are like a tree and its fruit: Any given species of tree will only produce the kind of fruit that the species produces, not the kind of fruit from another species. The analogy here is that a good heart will produce good deeds and speech and an evil hear will produce evil deeds and speech.
In logic, the kind of relationship describe by Jesus is called modus ponens, which says “X implies Y. X, therefore Y”. What one cannot do under this kind of relationship is say, “Y therefore X”. This is called affirming the consequence, which is not valid. However one can say, “X, therefore possibly Y”, which is an inference from evidence. In other words, if one has a good heart, then one will have good speech and deeds, but good speech and deeds don’t prove a good heart, rather they serve as evidence for a good heart. At times, people can “fake it”. Likewise, one can say “not Y, therefore not X”, which is called modus tollens. James makes this argument concerning the relationship between works and faith. He saying that he will show you his faith by his works inductively and without works, faith is dead via modus tollens (James 2:14-26). Works and speech are outward expressions of the inward change that happens when one believe in Christ, and there can be used to determine the condition of one’s heart. A person that calls himself a follower of Jesus yet does not do good in keeping with that faith has a questionable faith. But at the same time this isn’t necessarily a tale-tell sign of a Christian either. Jesus illustrated this with parables too concerning wheat and tares (Matthew 13:24-30), which are practically identical. Likewise, not everyone who says “Lord, Lord’ will be recognized by Jesus even though they seemingly did good things in his name (Matthew 7:21-22)
The Bible is explicitly clear: salvation comes by faith, not by works (Ephesians 2:8-9). But at the same time, works are evidence of this faith. Christians therefore ought to examine his or her own faith to make sure that he or she is not trusting in works or something else entire for salvation, rather in the completed work of Jesus. Likewise, this is not a license to go on a witch hunt to weed out the tares – in fact Jesus warns against this. Rather, again each should examine his own heart asking, “Do I call Jesus, ‘Lord’?” If not, then repent and believe the gospel! If so, “Am I obeying his commands?” If one can honestly answer “yes” answer these questions, then there is no need to worry about others questioning one’s faith based on works.
Lord, You are my Lord! Help me to follow your commands!