There are some dispensationalists who believe that during Jesus’ own ministry, Jesus converted his teaching from a works based salvation to a faith based salvation. They point to Jesus predicting his own death and resurrection as evidence of this. But the fact is that Jesus’ gospel remained unchanged during the entirety of his ministry. He always taught an imminent Kingdom of God on earth. When we encounter his later teachings about his own death and resurrection, it is always to his disciples, he often tells them to tell no one, and they generally don’t believe or understand him.

The first prediction is recorded in Luke 9, Mark 8, and Matthew 16. Here is the first indication that Christ gives to his disciples that he is going to die. Each text makes clear that Jesus is alone with his disciples. He then asks them who he is. When they respond he is the Christ, he tells them to tell no one. This is critical, because we learn this is a secret teaching to only 12 individuals. Both Matthew and Mark record further that one of his disciples (from other scripture we can infer all the disciples were perplexed), Peter, begins to rebuke him. Jesus then counter-rebukes Peter.

Luke’s account is the most concise:

Luk 9:18 And it came to pass, as he was alone praying, his disciples were with him: and he asked them, saying, Whom say the people that I am?
Luk 9:19 They answering said, John the Baptist; but some say, Elias; and others say, that one of the old prophets is risen again.
Luk 9:20 He said unto them, But whom say ye that I am? Peter answering said, The Christ of God.
Luk 9:21 And he straitly charged them, and commanded them to tell no man that thing;

All three authors saw the most important elements as those contained in this little section. Jesus was teaching his disciples (not the public). They stated he was the Messiah. Jesus then told them to tell no one. Mark further elaborates Jesus’ teachings:

Mar 8:27 And Jesus went out, and his disciples, into the towns of Caesarea Philippi: and by the way he asked his disciples, saying unto them, Whom do men say that I am?
Mar 8:28 And they answered, John the Baptist: but some say, Elias; and others, One of the prophets.
Mar 8:29 And he saith unto them, But whom say ye that I am? And Peter answereth and saith unto him, Thou art the Christ.
Mar 8:30 And he charged them that they should tell no man of him.

The basic intro is the same, but then it goes into detail about what he taught next:

Mar 8:31 And he began to teach them, that the Son of man must suffer many things, and be rejected of the elders, and of the chief priests, and scribes, and be killed, and after three days rise again.
Mar 8:32 And he spake that saying openly. And Peter took him, and began to rebuke him.
Mar 8:33 But when he had turned about and looked on his disciples, he rebuked Peter, saying, Get thee behind me, Satan: for thou savourest not the things that be of God, but the things that be of men.
Mar 8:34 And when he had called the people unto him with his disciples also, he said unto them…

Mark shows that he was preaching a Christ that would suffer and die. This is not what any Jew expected from a Messiah, so naturally his disciples rejected it. Peter rebukes him, gets called Satan and the story shifts to Jesus talking to the multitude (as contrasted only to his closest disciples). The story gives us no resolution as to the thoughts of Peter or any other disciple. In Matthew we see the same pattern:

Mat 16:13 When Jesus came into the coasts of Caesarea Philippi, he asked his disciples, saying, Whom do men say that I the Son of man am?
Mat 16:14 And they said, Some say that thou art John the Baptist: some, Elias; and others, Jeremias, or one of the prophets.
Mat 16:15 He saith unto them, But whom say ye that I am?
Mat 16:16 And Simon Peter answered and said, Thou art the Christ, the Son of the living God.
Mat 16:17 And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven.
Mat 16:18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
Mat 16:19 And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
Mat 16:20 Then charged he his disciples that they should tell no man that he was Jesus the Christ.

This gospel expands on his blessing to Peter (remember that Matthew is a Jewish gospel so wants to reinforce Peter’s authority), but keeps all the same basic elements. This gospel turns the next section into long term summary of his teachings. Jesus is said to teach only his disciples about his coming death and resurrection. There is reason to think his prohibition on telling others carries over to these teachings as well (see further down).

Mat 16:21 From that time forth began Jesus to shew unto his disciples, how that he must go unto Jerusalem, and suffer many things of the elders and chief priests and scribes, and be killed, and be raised again the third day.
Mat 16:22 Then Peter took him, and began to rebuke him, saying, Be it far from thee, Lord: this shall not be unto thee.
Mat 16:23 But he turned, and said unto Peter, Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men.

Matthew marks this event as the turning point when Jesus begins telling his disciples about his death and resurrection. Jesus attempts at great cost to keep this a secret from the general population. In Mark we see that Jesus uses subterfuge to remain unnoticed in order to teach these things (to his disciples):

Mar 9:30 And they departed thence, and passed through Galilee; and he would not that any man should know it.
Mar 9:31 For he taught his disciples, and said unto them, The Son of man is delivered into the hands of men, and they shall kill him; and after that he is killed, he shall rise the third day.
Mar 9:32 But they understood not that saying, and were afraid to ask him.

Jesus did not want any man to know it. Was this a legion of disciples he has been teaching all this time, or does the Bible use the word as we do, in order to mean the 12 disciples? It is hard to keep secret and remain hidden when multitudes know a secret. And if not, what does Judas betray to the High Priest, if not for his secret teachings that he is the Messiah and will die and rise again? Note also that none of the disciples understood his teachings. If Jesus was changing his ministry, it is odd that no one understood it. Compare this to Mark and Luke’s version:

Mat 17:22 And while they abode in Galilee, Jesus said unto them, The Son of man shall be betrayed into the hands of men:
Mat 17:23 And they shall kill him, and the third day he shall be raised again. And they were exceeding sorry.

Sorry here means vexed. This teaching unnerved them. Mark emphasizes they didn’t understand it while Matthew states they were troubled by it. Luke adds that this teaching was hidden from them (either reinforcing that they didn’t understand it or implying that Jesus actively tried to be ambiguous (both good indications that Jesus was teaching something secret, instead of a new gospel)):

Luk 9:44 Let these sayings sink down into your ears: for the Son of man shall be delivered into the hands of men.
Luk 9:45 But they understood not this saying, and it was hid from them, that they perceived it not: and they feared to ask him of that saying.

Matthew 20 records a third instance, this time leaving out anything about them not understanding or being sworn to secrecy:

Mat 20:17 And Jesus going up to Jerusalem took the twelve disciples apart in the way, and said unto them,
Mat 20:18 Behold, we go up to Jerusalem; and the Son of man shall be betrayed unto the chief priests and unto the scribes, and they shall condemn him to death,
Mat 20:19 And shall deliver him to the Gentiles to mock, and to scourge, and to crucify him: and the third day he shall rise again.

It cuts off after this, not elaborating on the events around this (similar to Mark 10:33). Luckily, Luke does that for us:

Luk 18:31 Then he took unto him the twelve, and said unto them, Behold, we go up to Jerusalem, and all things that are written by the prophets concerning the Son of man shall be accomplished.
Luk 18:32 For he shall be delivered unto the Gentiles, and shall be mocked, and spitefully entreated, and spitted on:
Luk 18:33 And they shall scourge him, and put him to death: and the third day he shall rise again.
Luk 18:34 And they understood none of these things: and this saying was hid from them, neither knew they the things which were spoken.

Again, the disciples do not understand.

So every time Jesus talks about anything related to the gospel as we know it, it is always to his disciples, it is never understood by anyone, it is widely rejected, and never is it tied to salvation (redeeming blood, a blood sacrifice, redemption, propitiation, or grace). Instead, the four gospels are laid out in a fashion we would expect. Jesus is introduced. His general gospel is explained. And any nuanced or secret teachings are revealed later. His public ministry was always about a coming Kingdom of God. It was never about his death and resurrection.