Let us look how Paul used the term
"son of" here when he spoke to Elymas::
"O full of all deceit and all fraud, you son of the devil, you enemy of all righteousness, will you not cease perverting the straight ways of the Lord?"
(Acts 13:10).
The Jews who heard this would understand that Paul was saying that Elymas' "nature" was that of the devil.
And when the Lord Jesus claimed to be the Son of God those who heard Him would understand Him to be saying that His very nature is that of God. And when He said that God is His Father and the Jews understood that He was claiming to be God:
"But Jesus answered them, My Father worketh hitherto, and I work. Therefore the Jews sought the more to kill him, because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God" (Jn.5:17-18).
If this was just a misunderstanding then surely the Lord Jesus would have denied that He was making Himself equal to God.
In fact, in the same discourse He claimed to be able to raise the dead (v.21) and said that the Father had committed all judgment to Him (v.22). He also said this:
"That all men should honour the Son, even as they honour the Father. He that honoureth not the Son honoureth not the Father which hath sent him" (v.23).
How do you explain what the Lord Jesus said there? If the Lord Jesus is not God then those words are the worst sort of blasphemy possible. How do you defend what the Lord Jesus said there?
The words of the Apostle John here cannot be mistaken:
"And we know that the Son of God is come, and hath given us an understanding, that we may know him that is true, and we are in him that is true, even in his Son Jesus Christ. This is the true God, and eternal life" (1 Jn.5:3-4).
Let us look at the words of Thomas again:
"And Thomas answered and said unto him, My Lord and my God" (Jn.20:28).
Of course when Thomas used the words "My Lord" he was not making an exclamation under his breath. After all, Jesus had told them that was the proper way to address Him (Jn.13:13). So when He said "and my God" there is absolutely no reason why anyone would believe that those words were nothing more than an exclamation under his breath.
Then how do you explain the words here in "bold"?:
"For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace" (Isa.9:6).