Although we cannot be certain, it is highly likely that those gathered at the temple had heard Jehovah’s voice from the Heavens pierce the darkness not a year earlier. This time, it is a regular day, even if it might have been a special feast day. There were no portents in the sky of a coming event. We might imagine a sunny day with a nice blue sky and white clouds. On that peaceful day, a voice again comes from Heaven.
The last time the voice had come from Heaven, the earth had been shaken. This time, the earth was calm, but the power of the voice “did pierce them … that there was no part of their frame that it did not cause to quake.” They might not have understood the voice at first, but they understood whose voice it was.
The declaration in verse 7 does two things. The first is that it announces that their long-awaited Messiah had come. It also defined a clear division between Father and Son. That understanding would be more important as Jesus taught. However, it was a distinction that was important at that time to indicate that even when God appeared on earth, there was no void in Heaven. The Father continued to watch over his children, even when the Son was on earth.