The Lord spoke in parables to hide things. The people did not see and hear, because their eyes and ears were closed. It was not given to them. In contrast to the disciples. They were allowed to hear it and it was made known to them.
16 But blessed are your eyes, because they see, and your ears, because they hear.
17 For, Amen! I say to you, many prophets and righteous men desired to see what you see, and they did not see it, and to hear what you hear, and they did not hear it.
happy
The Lord declares the disciples happy, because they see and hear. He made known to them what the meaning of the parable is, as we will see in the following verses. Would Jesus also have explained to them what the meaning of His actions was? That is implied, because the Lord also says that they see.
Jesus adds that many prophets and righteous men desired to see and hear these things, but it was not made known to them. The prophets examined their own prophecies, to discover how much time, and what kind of time, there would be between the suffering of the Messiah and His ‘glories’ that would follow.
1 Peter 1
10 Concerning this salvation the prophets sought and searched, who prophesied of the grace that would come to you,
11 and searched to see what, or what time, the Spirit of Christ which was in them made clear, testifying beforehand of the sufferings of Christ, and the glories that would follow.
the sufferings of Christ
That Christ would suffer was foretold in the Hebrew Bible. Think of Isaiah 53 where it says that He would be despised by His people, where it speaks of His stripes, that He would be bruised and numbered with the transgressors. He would be led as a lamb to the slaughter and be with a rich man in His death.
Or Psalm 22, where it is prophesied that God would abandon Him to His enemies. Here too it is said that He would be a reproach and would be despised. That dogs (=pagans) would surround Him, pierce His hands and feet and cast lots for His clothes.
the Emmaus pilgrims
It was precisely this suffering that would precede His glory, which the Emmaus pilgrims had no idea of. The Lord reproached them, because they should have known it, from the Scripture (Luke 24:25-26). They only knew a Messiah who would become King over His people, but had not understood that He had to suffer first.
the glory of the Messiah
The Hebrew prophets also speak clearly of the glory that would befall the Messiah. He will be recognized by His people as the One whom they pierced (Zech.12:10) and acknowledged as the Messiah. He will sit on the throne of His father David (Ps.132:11; Isa.9:6) and bring the scattered people back to the land (Deut.30:3; Ezek.37:12). Jerusalem will be the capital of the world to which the nations will come and all nations will be subject to Him (Isa.2:3-4).
what or what time
In his first epistle, Peter says that the prophets searched their own prophecies because they saw things that they did not understand. They searched to what time or what period their prophecies related. Of course, these prophets knew that the Lord would come to establish His Kingdom over this world and that this would be through Israel. They just did not know how much time, and what kind of time, would pass between His suffering and the glory of the Messianic kingdom of peace.
His coming as one whole
In the Hebrew prophets, the first coming of the Messiah and His second coming are often described as one whole. His humiliation is then immediately followed by His glory, without any space in between. See for example in Zech. 9:9-10. The time in between was hidden from them and it was later Paul who revealed this (Rom.16:25-26; Eph.3:3-6; Col.1:26).
interim
In the future, Christ will establish His Kingdom worldwide through Israel and the nations will share in the glory of the Messianic kingdom. That was no secret to the prophets, because the Tenach is full of it.
But now, in the present interim, in which Israel is unbelieving, the believers from the nations have a share in Christ himself! They belong to the ecclesia, the body of Christ (Eph.1:22-23).
This time in which the ecclesia is gathered, was hidden from the Hebrew prophets. They searched it in their own writings, but it was revealed to Paul, who revealed it in his letters.
glories
But why does Peter speak of glories, a plural? In the future, in the Messianic kingdom, His glory will be revealed to Israel and all nations. But even now in the period in which He is hidden, He has glory, even though it is still seen by very few.
Hebrews 2
9 But we see Jesus crowned with glory and honor…