It has long been recognised that in the Synoptic Gospels (Mark especially) Jesus is frequently recorded as commanding people not to speak about certain aspects of his identity and activity.

For example:

1. Jesus commonly taught the disciples separately from the crowds (Mark 4:13, 34; 7:17; 9:28–29, 30–31; 10:10–11; 13:3).
2. Jesus asked several people whom He healed and the family of a girl He brought back to life not to speak of it to anyone (Mark 1:43–44; 5:43; 7:36; 8:26).
3. After Jesus had healed a deafmute, Mk 7:36,.
4. He commanded demons who were privy to His true identity to be silent so that the crowds wouldn’t learn He was the Son of God (Mark 1:34; 1:24–25; 3:12, 11; 5:7).
5. After Peter confessed that Jesus was the Messiah, Jesus warned the disciples not to reveal His messianic identity to outsiders (Mt 16:20; Mk 8:29–30; Lk 9:21).
6. After His transfiguration (Mt 17:9; Mk 9:2–8), Jesus ordered Peter, James, and John not to tell anyone what they had witnessed—both the transfiguration and the heavenly voice that affirmed Jesus’ status as “My beloved Son.” He ordered them to stay silent “until the Son of Man had risen from the dead” (Mk 9:9 ESV).

In addition, Jesus’ self-designation as ‘Son of man’ has often been thought to imply a certain secretiveness.

Wrede

William Wrede (who coined the German term Messiasgeheimnis in 1901) maintained that Jesus did not speak of himself as Messiah.  Wrede cited Mk 9:9 and the disciples’ confusion after the crucifixion in favour of this hypothesis.  The disciples came to think of him as Messiah after they had formed the belief that he had risen from the dead (see Acts 2:36; Rom. 1:4).  They then read back a Messianic identity into the accounts of his life and ministry.  Mark’s ‘Messianic secret’ is therefore a device for explaining why no-one remembered Jesus as having claimed to be the Messiah during his lifetime.

Critics reply that this interpretation is inadequate, given that the (supposed) resurrection of John the Baptist (Mk 6:14) and the (actual) coming back to life of Lazarus (Jn 11:43f) did not confer Messianic status on those individuals.  A better explanation would be that Jesus’ resurrection vindicated what he had taught about himself all along.  He was indeed crucified for claiming to be Israel’s king, Mk 14:61–63; 15:2–31 (as Wrede himself later conceded).

An alternative approach

It is more plausible to reason that titles such as ‘Messiah’ and ‘Son of God’ carried different meanings and expectations, and would have been too readily misunderstood.  For many, these titles had political overtones and would have been seen as serious threats to both the Jewish and the Roman regime.  Overt claims to such status would have precipitated a premature crisis in Jesus’ ministry.  The full implications of such designations would not be realised until Jesus’ parousia, when he would return to judge and rule the nations.  Indeed, during his life-time, Jesus wished to emphasise that he was precisely not the kind of Messiah that many were expecting.  He chose rather to follow a path of humility and self-sacrifice (and taught his disciples to do the same).

Clement of Alexandria thought that to proclaim Jesus as Messiah at an early stage in his public ministry would have precipitated a crisis (either of adulation of antagonism), cut short his work of preaching and healing, and caused death by stoning (which was not predicted) rather than by crucifixion (which was).  (Brattston, D. (2020) Bible Problems Solved by Early Christians)

As Bock (Holman Apologetics Commentary) remarks:-

‘The Jewish expectation of the Messiah, which took on many forms, was consistently about a triumphant figure of power, whether an earthly king (Pss. Sol. 17-18), a transcendent being (1 Enoch 46), or a royal personage alongside a priestly Messiah as at Qumran (1QS 9:11-12). Contrary to this expectation, suffering was key to understanding Jesus and his mission. Widespread talk about Jesus’ identity as Messiah would lead to confusion or even opposition to Jesus’ true purposes, and for this reason he disallowed talk about his being the Messiah until the role of suffering was appreciated.’

Further considerations weaken Wrede’s case and strengthen the alternative approach:-

1. Mark’s silence is not only do do with Messiahship, but also the kingdom (Mk 4:10-12) and Jesus’ miracles (Mk 5:43).
2. Messianic titles are not always suppressed at all (see Mk 10:46-52).
3. If Jesus’ healing miracles had been publicised too widely, there would have been even more pressure to divert him from his chosen course of ministry (see Mk 1:44f; 2:2-4; 3:20f; 6:31).
4. There is actually a publicity element quite early on, as in Mk 5:19f.
5. Jesus would not allow demons to testify to him, even though they knew very well who he was.  Any acceptance by him of the demonic would have given ammunition to his opponents, who were keen to accuse him of being in league with Beelzebub, Mk 3:22.
6. The ‘secret’ is maintained mainly in the first half of Mark’s Gospel; consistent with Mark’s overall apocalyptic approach, there is a gradual revelation of Jesus’ identity as he discloses more of who he is and what he came to do.
7. There is, as Witherington remarks, an ‘inherent veiledness’ in Jesus’ preferred style of teaching, with its riddles, aphorisms and parables.  We should not be surprised if such indirect teaching applied to the King as well as to the Kingdom.

Lexham Bible Dictionary

Holman Apologetics Commentary

Dictionary of Jesus and the Gospels (2nd ed.)

Hard Sayings of the Bible