They came from Jesus' ministry. This ministry could be summed up as teaching. Certainly there were healings and signs, compassion and power, but all of this would serve the greater goal of teaching the men, “ordinary untrained men,” blue-collar folk, of no particular intellectual skill or status. Training them in the ministry of the kingdom of God, and all that that means.
Because of their lack of rabbinic training, which is I'm assuming an intentional choice on Jesus' part, the disciples were relatively “clean slates.” Like all good Jews, they probably attended synagogue, read the Scriptures, worshiped in the temple, etc. But we do not have here a group of great swelling OT exegetes.
Instead, setting off with him for three years, we have a group that is strikingly shape-able. They are wonderstruck at times. They are slow to catch on. But they want to see-- they are beset by a love for their teacher, one that produces a genuine desire to learn. One wonders if perhaps these were the criteria Jesus looked for in his choosing them: men who were able to be overcome with love for him. Men who would want to be around him. This would make great minds unnecessary. It would even marginalize any particular religious piety. Here were people who could come home after a day's work and enjoy eating dinner with you. They could enjoy conversation, and they would want to know a man like Jesus, no matter how peculiar or blasphemous he seemed.
And they watch him as he heals, teaches, extends compassion. Tells cryptic allegorical stories. And above all it seems, as he constantly circles back to this “kingdom of God” theme. They are puzzled. Sometimes they “catch” a thing or two. Gradually the light goes on, bit by bit, concerning his Messianic identity. What “Messiah” may during and directly after Jesus' life is still a formative (perhaps misinformed) seed in the minds of the disciples, just as “kingdom” is a rather fuzzy notion as well. “God” seems to be a clear enough word, although some days Jesus almost seems to be making some sleight-of-hand references suggesting that he somehow is God. Perhaps their very definition of “God” is being challenged at its root. Whatever the case, there is a haze, though perhaps clearing little by little, concerning what it is exactly that they have got themselves involved in.
Then the end comes. Tragedy strikes and all their expectations about Jesus' work seems to unravel in a few hours as he is arrested, tried, crucified, and buried like so many pretenders to Messiah-ship. This one seemed so different. Notwithstanding a strange report days afterward of his tomb being found empty, the disciples on the Emmaus road are crushed. And you would know it by looking at them.
Into this situation the risen Christ steps, at first keeping his identity veiled. The “stranger” on the road, hearing their story, seems to preach:
“O foolish ones, and slow of heart to believe all that the prophets have spoken! Was it not necessary that the Christ should suffer these things and enter into his glory?” And beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself. Luke 24:25-27
And he goes on. And on. And what he does is what Jesus did-- teaches them and fills them and illuminates meaning. He educates them, meaning he "educes", or draws out of them, that which dwells latently within them already via their Hebrew identity. His subject matter is something they've heard before, but probably not this holistically. Page by page, he takes them, as a learned expert in the Scriptures, through the canon of Law and Prophets, Psalms and Wisdom. And in reference to the horrific death of their best friend and teacher, he shows them exactly how this death was foretold, making clear the fulfillment of Messianic promise in Yehshua. From (this is crucial) the Bible. He spoke of the serpent in the wilderness. He recalls David's mysterious handling of Lordship in Psalm 110. He cites Joseph's mistreatment at the hands of his brothers. Of the Law and the Temple. Of the Exodus.
On and on he teaches. Gradually, the Word became “flesh” and dwelt among them. Jesus, it seems, is the real point of this whole enterprise; his death not only necessary, but intended. It is not the end of the story but the basis from which the new chapter will now proceed. Remember, we are not yet at Pentecost. We are not at the point at which tongues of fire descend and power is given from on high. We are at a teaching moment. We are still in the classroom. We are in the Hebrew Bible. Remember that these disciples don't have a theology of the cross, they're simply grieving it. Again at the inn in which Cleopas and his friend find themselves, bewildered and captured by his words
The he said to them, “These are my words that I spoke to you while I was still with you, that everything written about me in Law of Moses and the Prophets and the Psalms must be fulfilled.” Then he opened their minds to understand the Scriptures, and said to them, “Thus it is written, that the Christ should suffer and on the third day rise from the dead, and that repentance and forgiveness of sins should be proclaimed in his name to all nations, beginning from Jerusalem. You are witnesses of these things. And behold, I am sending the promise of my Father upon you. But stay in the city until you are clothed with power from on high.” Luke 24:44-49
“I already told you this,” he says. “But you didn't believe me. Everything God spoke to your fathers concerned me. My coming. My dying. My rising. This story is about me, not you.” This illumination is one of the foundations for the book of Acts. The Apostles must have this happen if they are to take the Gospel of the Kingdom to all nations. They must see Jesus as the centerpiece of the Story of God, of God's ongoing conversation with his people. They must associate the previous Friday with Messianic prophecy and identity. Pentecost cannot happen until they are seeded with the Word. (Mind you, this is a Word that they have “known” from their youth. It's part of synagogue life. It's embedded in the Jewish cultural consciousness. It's just not alive yet.) Because this will be the Spirit's tool for awakening them, and clothing them with power.