Behold, the former things are come to pass - That is, the former things which he had foretold. This is the evidence to which he appeals in proof that he alone was God, and this is the basis on which he calls upon them to believe that what he had predicted in regard to future things would also come to pass. He had by his prophets foretold events which had now been fulfilled, and this should lead them to confide in him alone as the true God.
And new things do I declare - Things pertaining to future events, relating to the coming of the Messiah, and to the universal prevalence of his religion in the world.
Before they spring forth - There is here a beautiful image. The metaphor is taken from plants and flowers, the word צמח tsâmach properly referring to the springing up of plants, or to their sending out shoots, buds, or flowers. The phrase literally means, ‘before they begin to germinate,’ that is, before there are any indications of life, or growth in the plant. The sense is, that God predicted the future events before there was anything by which it might be inferred that such occurrences would take place. It was not done by mere sagacity - as men like Burke and Canning may sometimes predict future events with great probability by marking certain political indications or developments. God did this when there were no such indications, and when it must have been done by mere omniscience. In this respect, all his predictions differ from the conjectures of man, and from all the reasonings which are founded on mere sagacity.