1. Before believing in Jesus as the Christ (Mt 26:33-35)
    Zech 13:7, Lk 24:19, 25-26, Mk 14:50, 71, Jn 2:22, Acts 4:11-12

In the Old Testament it was prophesied that people would forsake Christ as their Shepherd. (Zech 13:7)

Zech 13:7 Awake, O sword, against my shepherd, and against the man that is my fellow, saith the Lord of hosts: smite the shepherd, and the sheep shall be scattered: and I will turn mine hand upon the little ones.

Peter and his disciples told Jesus that they would not forsake Him. (Mt 26:33-35)

Mt 26:33 Peter answered and said unto him, Though all men shall be offended because of thee, yet will I never be offended.

34 Jesus said unto him, Verily I say unto thee, That this night, before the cock crow, thou shalt deny me thrice.

35 Peter said unto him, Though I should die with thee, yet will I not deny thee. Likewise also said all the disciples.

This was a time when they did not truly believe in Jesus as the Christ. They knew Jesus as a mighty prophet. (Lk 24:19)

Lk 24:19 And he said unto them, What things? And they said unto him, Concerning Jesus of Nazareth, which was a prophet mighty in deed and word before God and all the people:

Also, the Old Testament was not understood because it was not believed that Jesus was the Christ. (Lk 24:26-27)

Lk 24:26 Ought not Christ to have suffered these things, and to enter into his glory?
27 And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself.

In the end, as prophesied in the Old Testament, the disciples of Jesus abandoned Him and fled. Peter even cursed Jesus for fear that he might be caught. (Mk 14:50,71)

Mk 14:50 And they all forsook him, and fled.
71 But he began to curse and to swear, saying, I know not this man of whom ye speak.

After Jesus was resurrected, the disciples truly believed that Jesus was the Christ. Only then did they understand the Old Testament and the words of Jesus. (Jn 2:22)

Jn 2:22 When therefore he was risen from the dead, his disciples remembered that he had said this unto them; and they believed the scripture, and the word which Jesus had said.

After the disciples believed that Jesus was the Christ, they were able to preach that Jesus was the Christ even before death. (Acts 4:11-12)

Acts 4:11 This is the stone which was set at nought of you builders, which is become the head of the corner.
12 Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.