They shall perish - Nothing can be eternal a parte ante, or a parte post, but thyself. Even that which thou hast created, because not necessarily eternal, must be perishable; necessary duration belongs to God only; and it is by his will and energy alone that universal nature is preserved in existence, and preserved from running into speedy disorder, decay, and ruin.
Yea, all of them shall wax old - Every thing must deteriorate, unless preserved by thy renewing and invigorating energy. Even the heavens and the earth are subject to this law; for that which is not, from the infinite perfection of its own nature, Eternal, must be perishable; therefore the heavens and the earth must necessarily come to an end. They contain the seeds of their own dissolution. It is true that in sublunary things, the vicissitudes of seasons is a sort of check to the principle of dissolution; but it only partially corrects this tendency. Even the productions of the earth wear out or deteriorate. Plant the same seed or grain for several years consecutively, and it degenerates so as at last not to be worth the labor of tillage, however expensively the soil may be manured in which it is planted. I may instance in wheat and in the potatoe, the two grand supporters of life in European countries. All other seeds and plants, as far as they have fallen under my observation, are subject to the same law.
Of old - See this passage fully explained in the notes at Hebrews 1:10-12. In the beginning; at the first. The phrase used here means literally “to the face;” then, “before” in the order of time. It means here, long ago; of olden time; at the beginning. The meaning is, that the years of God had stretched through all the generations of people, and all the changes which had occurred upon the earth; that at the very beginning he existed, and that he would continue to exist to the very close, unchangeably the same.