Thank you for the interpretive question, “In Hebrews 12:25, who is “Him”?
As one reads the context of Hebrews 12, there is a reference to Moses-Israelites at Mount Sinai. There is the reference to the speaker at Mount Sinai. There is the reference to the speaker to the followers of Jesus Christ.
As one reads the Mount Sinai account of God descending and speaking to the Israelites, there are several options for one’s consideration. Here are the options to the reference of “him”:
A. God the Father spoke at Mount Sinai (Exodus 19:19)
B. The LORD God spoke at Mount Sinai (Exodus 20:1–2).
C. The angel of the LORD spoke at Mount Sinai (Acts 6:35–36).
As one observe and reads carefully the text, there is the reference to you (the believers of Jesus), and they is the reference to the Israelites, and then we, which would include the believers of Jesus and the writer of Hebrew and his companions. There is one speaker to both the Israelites at Mount Sinai and to the followers after the resurrection of Jesus. The writer of Hebrew warns the readers of this letter not to follow the example of the Israelites and rejected that once spoke to their forefathers.
Thus there are not two speakers, but one speaker to the forefathers and to them. I believe that person is the Second Person of the Godhead who revealed himself as YHWH and became incarnated in the flesh as Immanuel, God with us, the Son of God.
At the baptism of Jesus, a voice from heaven said this in Matthew 3:17, “And a voice from heaven said, “This is my Son, whom I loved; with him I am well pleased” (NIV). and again at the Mount of Transfiguration in Matthew 17 says this, “5 While he was still speaking, a bright cloud covered them, and a voice from the cloud said, “This is my Son, whom I love; with him I am well pleased. Listen to him!” (NIV). Throughout the Gospel of John, Jesus declared that he speaks the words of the Father. He does not speak on his own accord. Thus in my understanding of the Hebrew 12:25, the him is referring to YHWH who became the incarnated Son of God, Jesus. He was the one who spoke to the forefathers of the Israelites and the spoke person to the Jews.
SUMMARY: The reference of him in Hebrews 12:25 is YHWH or the incarnate Son of God, Jesus.
For more perspectives: