Charles Ellicott Commentary Isaiah 48:7

"They are created now, and not from of old; and before this day thou heardest them not; lest thou shouldest say, Behold, I knew them." — Isaiah 48:7 (ASV)

They are created now ... —The verb is an unusual one, as applied to the events of history. What is meant is that the things which had been from the beginning in the mind of God are now, for the first time, manifested through the prophet, as about to come to pass. What these are the prophet develops in the following chapters, as including the spiritual redemption and restoration of Israel. They were kept in store, as it were, to make people wonder (Romans 16:25–26).

Even before the day when ... —Better, and before today you did not hear them .... The reason given for what we might almost call this method of reserve and reticence was that the people had been until now unprepared to receive the truth, and in their state, it would only have increased their condemnation (John 16:12; Mark 4:33).