John Calvin Commentary Acts 27:23

"For there stood by me this night an angel of the God whose I am, whom also I serve," — Acts 27:23 (ASV)

For there stood by me. So that he might not be accused of rashness for so confidently promising that they would all be safe, he presents God as his source and witness. Nor is it to be doubted that he was fully persuaded that it was a true vision, so he did not fear Satan’s deceptions.

Because the father of lies often deceives people under the guise of revelations, God never appeared to His servants, either by Himself or by His angels, without removing their doubt by showing them some clear and evident signs; and secondly, He equipped them with the spirit of discernment, so that they would not be deceived.

But Paul extols the name of His God in plain words among unbelievers, not only so that they might learn that the true God is worshipped in Judea, but also that Paul himself worships Him.

They all knew why he was imprisoned. Now, seeing angels come down to him from heaven, they could easily gather that his cause was approved by God. Therefore, there is in these words an implicit commendation of the gospel.

Nevertheless, we see how Paul triumphs in his bonds, as he becomes the agent of safety for so many people, and God’s interpreter.