Your question is not naive. Nor is there a single answer.
- No sign. Some Jews expected the Messiah to perform an outstanding miracle. Moses prophesied this:
15 The Lord your God will raise up for you a prophet like me from
among you, from your fellow Israelites. You must listen to him.
(Deuteronomy 18:15)
Since Moses performed ten plagues against Egypt, parted the Red Sea, called down Manna from heaven, received the Ten Commandments, and was spoke to by God in the presence of witnesses, this set their expectations. Jesus performed many healings, but nothing as spectacular as Moses - except for raising Lazarus and Jairus' daughter from the dead and then himself rising from the dead. However - no human witnessed Jesus rise, and only his disciples saw him after he rose and saw him ascend into heaven. The general Jewish population and the leaders never saw that sign.
Indeed, Jesus told them that they would not get the sign that they wanted:
29 As the crowds increased, Jesus said, “This is a wicked generation.
It asks for a sign, but none will be given it except the sign of
Jonah. 30 For as Jonah was a sign to the Ninevites, so also will the
Son of Man be to this generation. 31 The Queen of the South will rise
at the judgment with the people of this generation and condemn them,
for she came from the ends of the earth to listen to Solomon’s wisdom;
and now something greater than Solomon is here. 32 The men of Nineveh
will stand up at the judgment with this generation and condemn it, for
they repented at the preaching of Jonah; and now something greater
than Jonah is here. (Luke 11:29-32)
The thing about the sign of Jonah is that it was a sign to Gentiles, the Ninevites.
- Political expectations. The Jews expected a political leader who would lead them in a revolt and free them from Roman rule. Some people were willing to entertain the idea that Jesus could be the Messiah, but his response to them turned them off:
14 After the people saw the sign Jesus performed, they began to say,
“Surely this is the Prophet who is to come into the world.” 15 Jesus,
knowing that they intended to come and make him king by force,
withdrew again to a mountain by himself. (John 6:14-15)
Jesus' disciples were not free from this expectation:
6 Then they gathered around him and asked him, “Lord, are you at this
time going to restore the kingdom to Israel?” (Acts 1:6)
- Doctrinal divisions. The Pharisees believed in an afterlife and that God can ressurect people, but the Sadducees did not:
18 Then the Sadducees, who say there is no resurrection, came to him
with a question. (Mark 12:18)
- Source of authority. The Jews questioned Jesus about where he received his authority. His answer forced them to accept him on faith, not a sign.
23 Jesus entered the temple courts, and, while he was teaching, the
chief priests and the elders of the people came to him. “By what
authority are you doing these things?” they asked. “And who gave you
this authority?”
24 Jesus replied, “I will also ask you one question. If you answer me,
I will tell you by what authority I am doing these things. 25 John’s
baptism—where did it come from? Was it from heaven, or of human
origin?”
They discussed it among themselves and said, “If we say, ‘From
heaven,’ he will ask, ‘Then why didn’t you believe him?’ 26 But if we
say, ‘Of human origin’—we are afraid of the people, for they all hold
that John was a prophet.”
27 So they answered Jesus, “We don’t know.”
Then he said, “Neither will I tell you by what authority I am doing
these things. (Matthew 21:23-27)
Interestingly enough, John the Baptist, growing impatient and disillusioned while in prison, also questioned Jesus through his emissaries:
18 John’s disciples told him about all these things. Calling two of
them, 19 he sent them to the Lord to ask, “Are you the one who is to
come, or should we expect someone else?”
20 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?’”
21 At that very time Jesus cured many who had diseases, sicknesses and
evil spirits, and gave sight to many who were blind. 22 So he replied
to the messengers, “Go back and report to John what you have seen and
heard: The blind receive sight, the lame walk, those who have
leprosy are cleansed, the deaf hear, the dead are raised, and the
good news is proclaimed to the poor. 23 Blessed is anyone who does not
stumble on account of me.” (Luke 7:18-23)
Jesus was asking John if he believed the prophets. All the things listed were associated with the coming of the Messiah. Jesus was calling on John to trust the Word of God as his sign. This is similar to the parable Jesus told about the rich man and Lazarus. The rich man wants a sign to be given to his brothers to save them from Hell, but Jesus says that the Words of Moses and the Prophets should be enough.
31 “He said to him, ‘If they do not listen to Moses and the Prophets,
they will not be convinced even if someone rises from the dead.’”
(Luke 16:31)
The Law, misinterpreted. Following from the question about authority, are issues arising from Jesus' and his disciples behavior. Healing on the sabbath, eating grain on the sabbath, associating with tax collectors and sinners, forgiving a sinful woman, and related things. Jesus as the very embodiment of God's law is free to interpret it in a perfect way, guaranteed to diverge from imperfect human traditions. Since there were so many ways that their interpretation differed from God's original intent and the law of mercy, Jesus was bound to do things of which they disaproved.
God's Sovereign will. The Scribes, Pharisees, and Saduccees sent people to question Jesus frequently. They did test him with their questions repeatedly. But it was God's sovereign will that Jesus be rejected.
22 “Fellow Israelites, listen to this: Jesus of Nazareth was a man
accredited by God to you by miracles, wonders and signs, which God did
among you through him, as you yourselves know. 23 This man was handed
over to you by God’s deliberate plan and foreknowledge; and you, with
the help of wicked men, put him to death by nailing him to the cross.
(Acts 2:22-23)
Paul has a lot to say about this in Romans 9, but that is a lot of Bible to quote. Paul says a lot about election and God's purpose in using the gift of salvation to the Gentiles in order to make the Jews jealous and ultimately save them.
So God brought about a cultural situation in Israel with so many conflicting forces that despite a huge number of miracles (tens of thousands healed, fed, freed from possession, etc.) that he would be able to do all that and yet demonstrate the hardness of the people's hearts, just as he did with Pharaoh. Salvation comes to the repentant, and Jesus needed to demonstrate the magnitude of the sin in their hearts in order to show just how bad we all need a savior. The messiah does not come without cost.
A new order of Growth. Moses introduced the people to God in this order:
- Miraculous external acts of power - the Exodus
- Emotional changes - rejoicing, loyalty, trust in Moses' leadership
- God's Law - delivered on Sinai
Jesus, however, called for things to proceed in reverse. Small seeds grow into big trees. In Jesus' parable of the soils in Matthew 13, Satan first tries to snatch the word (the Law), then scare people through persecution and hardship (emotion), then confuse our priorities in matters related to how we interact with the world. This suggest the following order of Jesus' work among people:
- The Son of God / the Truth - transforms your mind
- The Holy Spirit / Comforter - reorders your emotions, provides comfort, courage, hope
- God the Father / Provider - reorders your priorities and sovereignly provides your needs, sometimes through acts of power
Jesus led with the truth; following his death he sent the Holy Spirit, and only then began to act in power through his church. The Jews were expecting the Messiah to follow the same order as Moses, starting with the big things, but instead, he started with the small things andmade them grow.