What does Jesus' statement mean?
Why are they like "unmarked graves"? And what does he mean by "which people walk over without knowing it."?
The word "unmarked" comes from the Greek word ἄδηλος (adēlos) which means, according to the lexicon, "not manifest, indistinct, uncertain, obscure."
And the word "graves" here is translated from the Greek word μνημεῖον (mnēmeion), which relates to "any visible object for preserving or recalling the memory of any person or thing - a memorial, monument, specifically, a sepulchral monument to a tomb or burial site," as well as "tomb."
So while one could certainly translate this to an "unmarked grave" - typically an "unmarked grave" will at least have some indication that it is a grave - in other words, there will be some sort of tombstone, but without the name of the person who is buried there.
Jesus is speaking of complete obscurity here. Ordinarily, people will not walk over a grave, even if it is an unmarked grave.
But if the grave or burial site is completely obscured - no one knows it is a burial site - then people may easily walk over that site without knowing its contents.
But what does this have to do with the Pharisees?
Jesus had just mentioned that the Pharisees like to be seen and respected:
"Woe to you Pharisees, because you love the most important seats in the synagogues and respectful greetings in the marketplaces." (Luke 11:43)So we know that it is not as if the Pharisees are obscure. As Jesus indicates, they are anything but obscure.
The Pharisees were influential
What Jesus is speaking of is their ability to affect the spiritual lives of their followers. Jesus is indicating that their teachings have no spiritual power: They had no ability to change a person's heart or purify one's consciousness. They might be repeating the 'party line' of their institutions - but their teachings have no real power or authority.
This is because - even though they supposedly were representing the Jewish institutions and thus supposedly God - they were not representing the Supreme Being.
They had been appointed or elected to their posts by councils of men. Thus they were occupying political positions, and they were representing those who elected them - not the Supreme Being.
Plus they were occupying professional political posts. The Pharisees were paid for their posts, either by being given quarters and food or through paid salaries or both. The Pharisees and the Sadducees opposed each other in terms of interpretation of the Hebrew scriptures, but the Pharisees emerged as the group that wielded the most political clout - and were thus supported by the Romans.
We also know from the scriptures that the Pharisees, along with the chief priests, were involved in the persecution of Jesus:
The next day, the one after Preparation Day, the chief priests and the Pharisees went to Pilate. (Matt. 27:62)
They were not representing God
The underlying statement Jesus is making here is that these Pharisees - along with the chief priests - were not representing the Supreme Being. They were representing their sectarian institutions and their own desires for power and authority. This is why they wanted to get rid of Jesus - because he threatened their authority.
Unlike the false authority these institutional teachers bring, the Supreme Being grants real authority to change people's hearts. This authority comes in the form of empowerment, which is granted only to those involved in a confidential loving relationship with the Supreme Being.
This relationship is based on devotion and commitment. Such a person who becomes devoted to the Supreme Being may become empowered by the Supreme Being to represent Him as the Supreme Being wishes. As such, the selection of who represents the Supreme Being must ultimately come from the Supreme Being.
Yes, they may be introduced to the Supreme Being by one of His representatives - as illustrated in the scriptures with Jesus' own students, Jesus approaching John, and prophets being students of other prophets.
But the sign of someone who is not representing the Supreme Being is that they have been elected or selected by a council of men, a committee of men, or even one man. Such a selection is not the selection of God. It is the appointment or selection of humans.
One might ask: But what if that selection comes from God's representative?
The assumption is that God's representative would act on behalf of the Supreme Being and select or appoint his successor(s). But this is not the case.
A true representative of God does not select who can have a confidential relationship with God. This is between the Supreme Being and the individual. God's representative might be teaching on God's behalf, but he recognizes that it is ultimately the Supreme Being who exchanges a relationship with each person and thus empowers a person to represent Him.
While God's representative will teach people personally - introducing them to the Supreme Being - it is not up to God's representative to choose who will eventually develop their confidential loving relationship with the Supreme Being. This is illustrated by John the Baptist sending his students to ask Jesus:
John's disciples told him about all these things.... When the men came to Jesus, they said, "John the Baptist sent us to you to ask, 'Are you the one who is to come, or should we expect someone else?' " (Luke 7:18-20)And Jesus told his own disciples and students:
"Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son [Representative] and of the Holy Spirit, and teaching them to obey everything I have commanded you." (Matt. 27:19-20)We can see here that neither Jesus nor John chose or selected a successor. They taught to everyone, and accepted those who were serious as students and disciples. And they told them to go out and pass on those teachings to others.
But it was up to each individual to develop their relationship with God. Yes, the Supreme Being is not a vague force or void. And there is no automatic process. The Supreme Being is a Person. This is why God's representative teaches us to love the Supreme Being. How could someone love a void or vague force? For there to be love, there must be distinct individuals.
God chooses who represents Him
A real representative of God will recognize that it is the Supreme Being's prerogative in terms of who will represent Him.
God's representative offers his wisdom to everyone who is willing to hear. There is no exclusion. There is no selection. Jesus stood up on hills and in courtyards, preaching to whoever would come and listen - even Pharisees. And John the Baptist invited anyone and everyone - even Pharisees and chief priests - to come to the desert and hear his teachers.
As such, God's representative is offering his teachings about God to everyone who becomes serious enough to respect those teachings. There is no exclusion. There is no selection.
Appointment and selection are certainly attractive to some. In fact, they attract those who want the admiration and respect of others. Those who want to attract followers and receive the admiration of others are attracted to the process of appointment. But this is a materialistic desire. It has nothing to do with one's personal relationship with the Supreme Being.
And those who receive the appointments or selections of others within institutions will represent those institutions instead of representing the Supreme Being. This is why those teachers and leaders of the Catholic institution have allowed some of their teachers to continue in their positions even though they molested some of their followers. Because they consider the institution's reputation to be more important than pleasing the Supreme Being.
The bottom line is that Jesus is indicating that these institutional teachers have no real authority from the Supreme Being. They have not been empowered by the Supreme Being and thus cannot change people's hearts. They cannot have the kind of effect that Jesus had upon his followers - and the kind of effect that other prophets such as Moses and Abraham had upon their followers.
Those effects, communicated over the centuries within scripture, did not disappear. Those who sincerely read Jesus' teachings even today will be personally affected by those teachings. Jesus' teachings have the power - even though all the misinterpretation - of changing one's heart from being self-centered to being God-centered.
This is because Jesus was empowered by the Supreme Being, due to the fact that Jesus was pleasing to the Supreme Being:
And a voice from heaven said, “This is my Son [Representative], whom I love; with him I am well pleased.” (Matt. 3:17)Jesus also clarified this empowerment by the Supreme Being, based on his mission to please the Supreme Being:
"By myself I can do nothing; I judge only as I hear, and my judgment is just, for I seek not to please myself but Him who sent me." (John 5:30)