We can certainly make sweeping observations about people in general from this statement. But there is a context to Jesus' points that must be clearly understood. And getting that context allows us to not only understand the purpose of Jesus' statement but how it can be applied to our personal lives today.
We need to understand the audience and circumstances surrounding Jesus at the time of his statement. We know that Jesus was speaking to his students and disciples, confirmed by the statement just prior to the beginning of his lecture:
'Looking at his disciples, he said...' (Luke 6:20)
This means he was directly instructing his disciples. This is also confirmed by other statements within his lecture that are obviously pointed towards his students, such as:
"Blessed are you when men hate you, when they exclude you and insult you and reject your name as evil, because of the Son of Man." (Luke 6:22)We can thus arrive at the conclusion that key elements of Jesus' lecture were not intended for the general populace, as not everyone in the crowd was committed to Jesus to the point where they were willing to undergo the rejection and hatred of others by following Jesus.
This relates to time and circumstance
Jesus was preaching outside the confines of the ecclesiastical Jewish institution of his time. This Jewish institution and their teachers largely rejected and criticized Jesus' teachings, as evidenced throughout the New Testament. And we can tell by Jesus' statements here and elsewhere that those who followed Jesus were ostracized by the teachers and followers of the two primary ecclesiastical Jewish institutions (represented by the pharisees and sadducees).
But we should also remember that there was also a large crowd of non-disciples around Jesus as he was speaking this. So we can know that this most certainly was also spoken for the benefit of others who were not disciples. Consider the setting:
He went down with them and stood on a level place. A large crowd of his disciples was there and a great number of people from all over Judea, from Jerusalem, and from the coast of Tyre and Sidon, who had come to hear him and to be healed of their diseases. (Luke 6:17-18)So we know that there are two main audiences here: A large number of Jesus' disciples (indicating of course that Jesus had significantly more than twelve disciples); and a large crowd of interested people who had heard of Jesus' curative powers and were interested in being healed and even hearing his teachings.
We also can understand the frame of reference to Jesus' statement. Prior to this statement, Jesus said:
"Why do you look at the speck of sawdust in your brother's eye and pay no attention to the plank in your own eye? How can you say to your brother, 'Brother, let me take the speck out of your eye,' when you yourself fail to see the plank in your own eye? You hypocrite, first take the plank out of your eye, and then you will see clearly to remove the speck from your brother's eye." (Luke 6:41-42)
The purpose of Jesus' statement
Here we can see the dual purpose of Jesus' prior statement. Not only is he giving his students a lesson on becoming good students (following his teachings) before trying to teach others: He was also speaking to others about hypocritical teachers.
Thus we can arrive at the direction of Jesus' statement here. We can see that Jesus wanted his students to become qualified teachers - and not hypocrites - and he wanted those who were not following him to be able to determine who was truly qualified to teach.
This contrasted the ecclesiastical Jewish teachers with Jesus. Jesus was focused upon differentiating himself from the teachers of the ecclesiastical Jewish temples - the pharisees, sadducees and high priests. And now he was providing a clear and simple method to help people decide whose teachings they should follow.
Teaching and fruits
This also means that today we can apply this same method to assess today's teachers and their institutions. Consider carefully the first element of this method:
"No good tree bears bad fruit, nor does a bad tree bear good fruit."This provides a clear method for qualifying who we should accept as teaching the truth about the Supreme Being. It is quite simple. It does not require that we have to pry into the private lives of those who are preaching. All it means is that we can understand them by the "fruits" they produce.
Of course, Jesus is using the idea of "fruit" metaphorically. By "fruit" he means those things that come forth from the teacher. This means, first and foremost, their words. This is confirmed by Jesus' clear statement:
"For out of the overflow of his heart his mouth speaks."This indicates clearly that it is not just comparing what a person says with what they do. For Jesus clearly indicates that we can quite simply judge a teacher by what comes out of his mouth - his teachings.
This is often overlooked, as many focus on the concept of "practice what you preach." Yes, one should practice what they preach, but what about preaching the truth? Isn't that more important?
Let's say that a priest teaches in his sermons basically that as long as we come to church, confess our sins, give our tithings and proclaim 'Jesus is my savior' then we are saved. The priest could certainly practice what he is preaching by molesting young children during his off-duty hours, and then come to church, give his (confidential) confession to his superior, give up some of his Church paycheck and proclaim 'Jesus is my savior.'
Or say an evangelist preacher teaches that we can focus our lives upon getting rich and powerful as long as we ask Jesus and give thanks to Jesus for our wealth. He would certainly be "practicing what he preached" as he focuses his own life upon collecting tithings from his evangelism and padding his bank account with the funds, as we have seen with some.
But does just "practicing what they preach" mean that what they preach is right? Certainly not.
We must therefore examine their teachings carefully. This is Jesus' clear statement here. We can also look at the activities of the preacher or institution as we assess whether we want to follow them. We can also examine the institutional practices to assess the qualifications of that institution.
For example, we can look at the covering up of priest molestations within the Catholic church, and the centuries of torture and violence of the Church as we assess whether we want to follow the Church's teachings. We can look at the selective imprisonment of students and teachers within some other later sects. We can look at the forced indoctrination and even violence of evangelist teachers like Jim Jones - who forced the suicide of hundreds of followers - and others. Surely these "fruits" can tell us a lot about those teachers, just as the "fruits" of the ecclesiastical Jewish temples of Jesus' day indicated "bad fruits" were coming from these "bad trees."
But Jesus puts emphasis on the words - their teachings - as a primary way to assess the qualification of the teacher. This is because, as Jesus states:
"The good man brings good things out of the good stored up in his heart, and the evil man brings evil things out of the evil stored up in his heart. For out of the overflow of his heart his mouth speaks."In other words, a person can appear very pious - giving charity and visiting hospitals. They can appear to others as being so saintly and charitable. But how do we know they are not just doing all this just to make a show in order to capitalize on the fame and attention they receive from others? We have of course seen this in the life of a certain professional bicyclist, whose charitable activities convinced millions that he could not have cheated during his bike races.
So it is very difficult to know whether a person is teaching the truth simply by knowing some of his or her activities. This is because a snapshot of some activities can outwardly be deceiving.
Gauging the qualified teacher
But as Jesus says, it is way easier to gauge the qualified teacher simply by checking their words. What are they teaching? Does their teaching make sense? Does their teaching answer the practical questions, such as who am I and why am I here? Does their teaching explain why there is so much suffering in the world? Does their teaching teach me about who God is and how I can come closer to Him? Are their teachings consistent with Scripture?
These general questions should be the first line of questioning when it comes to qualifying who we should accept as a spiritual teacher.
Along with these, however, should be questions about how the teacher knows what he/she knows: Did they make up their teaching? Are they speculating? What is the source of their teachings?
These questions are important in spiritual life because we are talking about spiritual knowledge. We are talking about knowledge that cannot be ascertained through the physical senses.
For most religious institutions, the spiritual teacher is chosen because he or she graduated from a seminary college and received a certification of their being a minister. So who is qualifying them? In these fee-based (tuition) seminary colleges, a person simply pays a fee, passes the tests and gets the paper. The assumption is that since they passed the tests, they learned the material. They fully understood the doctrine of that particular institution.
But is that doctrine correct? Is that doctrine the Truth? Is it coming from God or just coming from some previous speculator in the past?
Made up teachings?
The Roman Catholic Church took over the Christian doctrine by force in the Fourth century AD and drove a set of speculative principles called the Nicene Creed - voted in place by a politically-driven council appointed by the Roman Emperor Constantine.
The doctrines of many other sectarian institutions that have followed have typically come from one influential person's personal "vision" or "realization," embellished by those following them. How do we know their "realization" or "vision" came from God? How do we know they didn't just make the whole thing up?
Again, this all comes down to what they are teaching and the source of their teachings. Did they make up their teaching or does it come - as Jesus' did - through a lineage of devoted teachers before him? And does it make sense? Does it answer all the questions concerning who we are and why we are here?
For example, some sectarian teachers teach that believers will rise up out of their graves to "inherit the earth" when the second coming of Jesus happens. Does this make sense though? If we were to dig up most of the graves of the early teachers who promulgated this philosophy we would find their decomposed remains. Their bodies certainly didn't rise up out of the grave. Their bodies decomposed, leaving dirt and a few bone fragments. How could they rise up out of the grave then?
These kinds of logical questions must be asked of our teachers before we accept their teachings. This is made clear by Jesus' statement here.
This means that we have to check the teacher's teachings. How do we do this? We can check their teachings with scripture, and we can check their teachings with the Holy Spirit within. Each of us has the ability to check the truth from within - from the Holy Spirit - if we are listening carefully to what is being taught.
As far as checking teachings against scripture, there are many scriptural passages that can be taken out of context and applied in some speculative way. We must therefore be able to see the difference between allegory and practical statements.
Every teacher within the Bible used allegory and symbolism according to the time and circumstance to describe the spiritual world and the spiritual path. Why? Because they were trying to utilize concepts that people could relate to as they described the spiritual realm - which is outside the physical dimension.
This is why the Holy Spirit must also confirm their teachings from within. The Holy Spirit is God's expansion from the spiritual dimension.
So while a teaching must make sense, and be consistent with the world around us; it must also be consistent with what is coming from the Holy Spirit within. It must also be consistent with scripture. The central governing principle laid out in the scriptures - the foundation for any bonafide doctrine - was made clear by Jesus and Moses:
"'Love the Lord your God with all your heart and with all your soul and with all your strength and with all your mind'" (Luke 10:27 and Deuteronomy 6:5)