Did they disobey Moses, Jesus, or the oracles?
Acts 7 (BLB) - 37 This is the Moses having said to the sons of Israel, 'God will raise up for you a prophet like me out from your brothers.' 38 This is the one having been in the congregation in the wilderness with the angel speaking to him in Mount Sinai, and who was with our fathers. He received living oracles to give to us, 39 to whom our fathers were not willing to be obedient, but thrust away, and turned back in their hearts to Egypt,
All of the above.
They would not obey Moses who gave them the oracles from God. So, most directly, they would not obey Moses. Moses was the representation of God’s authority to them, so disobedience to Moses was the same as disobeying the oracles or disobeying God.
At this point in the address of Stephen (Acts 7:39), the reference is to the unwillingness to obey as revealed through Moses.
Jesus referenced in Acts 7:45 is the Greek form of “Joshua” referencing the successor of Moses. Jesus Christ had not been revealed to them at that time as He has been to us, but when Jesus Christ was revealed, they refused to obey Him. Stephen was stoned upon making the accusation that they were unwilling to obey by any revelation or messenger (Acts 7:53).
37 It was this Moses who said to the Israelites, ‘God will raise up for you, from among your own kinsfolk, a prophet like me.’ 38 It was he who, in the assembly in the desert, was with the angel who spoke to him on Mount Sinai and with our ancestors, and he received living utterances to hand on to us. 39 Our ancestors were unwilling to obey him; instead, they pushed him aside and in their hearts turned back to Egypt.
The clear referent here is Moses. It was Moses who prophesied the coming of one like him. It was Moses who was with the angel of God on Mt. Sinai. And it was Moses whom our ancestors were unwilling to obey, pushing him aside and turning back to Egypt in their hearts. Of course, Stephen would also believe that his ancestors did not obey the oracles, since Moses was God's representative who conveyed God's message to the Israelites.
Stephen does not mention Jesus in this passage. Jesus was not alive on earth during the Exodus, so Stephen does not refer to him here - at least not directly, except insofar as Jesus is thought to have been present as the Second Person of the Trinity.
The answer in is found in the text itself as quoted in the OP's question. To show this, let me quote Acts 7:37-39 from the OP (with my overly literal translation):
37 This is the Moses having said to the sons of Israel, 'God will raise up for you a prophet like me out from your brothers.' 38 This is the one [Moses] having been in the congregation in the wilderness with the angel speaking to him [Moses] in Mount Sinai, and of our fathers who [Moses] received living oracles to give to us, 39 to whom [Moses] our fathers were not willing to be obedient, but thrust away, and turned back in their hearts to Egypt,
Thus, all the pronouns refer to Moses. That is, we have a similar chain of revelation as listed in Rev 1:1-3, namely:
Then we read that the people were unwilling to be obedient to these oracles that came from God via the angel and Moses. That is, disobeying the divine oracles is disobeying the instruction of God and thus, disobeying God whose messages arrived via the angel and Moses.
Note that Moses did not write the oracles - they were originated by God and thus, disobeying the oracles is disobeying their author, God.
In Acts 7:37-39, to understand whether the Israelites were disobeying Moses, Jesus or the oracles, the context must be considered, as Stephen was building up his defense against the false accusation made, that could result in him being stoned to death. He had taken 35 verses to detail historic events regarding the Israelites and Moses. But it is verse 35 that gives the answer.
"This Moses whom they refused, saying, Who made thee a ruler and a judge? ..." Acts 7:35 A.V.
So, in the first case, it was refusing Moses that was the act of disobedience, for the verse goes on to say that God made this Moses to be their ruler. This means that, in the second case, they also refused God by refusing his appointed ruler.
There is a third case, however, and that applies to the Israelites Stephen was addressing. They were listening to his witness, his testimony about whether Jesus of Nazareth had (as some of them claimed) said he would destroy the place of the Jews, and change the customs Moses had delivered to them (chapter 6 vs.13). Now, it took Stephen 36 verses to get to that point. In verse 37, Stephen then quoted Moses who had foretold God raising up a prophet like unto him, who they were to hear - that was the oracle. That one foretold in the oracle was Jesus Christ who they had put to death.
This means that the answer to the question is that the Israelites back then disobeyed God and Moses ; and the Israelites Stephen addressed face to face in his day disobeyed God, Moses, the oracle, and the Christ foretold in that oracle.
It is not as straightforward as merely reading three verses. To truly understand Stephen's defense, we must delve into the entire context of his argument and explore the logical narrative he presents.
In Acts 6:12-15, Stephen was seized and brought before the Sanhedrin for trial. His opponents presented false witnesses, accusing him of preaching about "this Jesus of Nazareth", and alleging that Jesus had spoken of the destruction of the Holy Temple and the alternation of the customs handed down by Moses to the Israelites.
In Acts 7, Stephens addresses his opponents, fellow Israelites, reminding them their patriarchs. He draws a parallel with Moses, whom they once rejected, referring to him as "This Moses"(Acts 7:35,37), echoing the Israelites' words: "Who made you ruler and judge over us?" (Acts 7:27). Stephen underscores their historical rejection by repeating this statement in Acts 7:35. However, despite their rejection, God chose Moses to lead the Israelites out of Egypt.
Stephen extends this analogy to Jesus, the focal point of the Sanhedrin's opposition. He implies that like Moses, Jesus-referred by his opponents as "this Jesus of Nazareth"-is being wrongly betrayed and murdered by the Sanhedrin. Stephen suggests that the Sanhedrin is repeating the errors of their ancestors by rejecting Jesus, whom God had foretold through the prophecies of Moses as the Righteous One chosen for the Israelites.
Who did the Israelites not obeyed?
The short answer is "God".
