John Calvin 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)

Now for the first time have they been created. The Prophet shows that he is not reasoning about things that are known or that have been learned by actual experience; and his object is not merely to correct that haughtiness which is natural to all men (for they claim for themselves what belongs to God alone), but also that no part of this event may be ascribed to fortune or to any other cause. In various ways do men rob God of the glory that is due to him, and direct all their faculties towards distributing among creatures what belongs to Him alone, so as to leave Him nothing but a bare and empty name. So that the people might not think that they had been defeated by the power of the Babylonians, or that it was by human strength or by chance that they were afterwards restored to liberty, for this reason he so frequently repeats and reiterates that this is the work of God.

Thou hadst not heard those things. When he affirms that “they had not heard them,” some explain this to mean that the people rejected God’s warnings and did not listen to good counsel. But I think that the Prophet’s meaning was different: namely, that what could not be known by human sagacity, and what had been unknown to the Jews, has been revealed in such a manner that they cannot defraud the Holy Spirit of the praise which is due to him; and this is very evident from the context.