Charles Ellicott Commentary Jeremiah 31:35-36

"Thus saith Jehovah, who giveth the sun for a light by day, and the ordinances of the moon and of the stars for a light by night, who stirreth up the sea, so that the waves thereof roar; Jehovah of hosts is his name: If these ordinances depart from before me, saith Jehovah, then the seed of Israel also shall cease from being a nation before me for ever." — Jeremiah 31:35-36 (ASV)

Which giveth the sun for a light by day ... —The leading thought in the lofty language of this passage is that the reign of law which we recognise in God’s creative work has its counterpart in His spiritual kingdom. The stability and permanence of natural order is a pledge and earnest of the fulfilment of His promises to Israel as a people. The new Covenant of pardon and illumination is to be eternal in its duration, which the first Covenant was not. We have learnt, through the teaching of St. Paul, while not excluding Israel according to the flesh from its share in that fulfilment, to extend its range to the children of the faith of Abraham, the true Israel of God (Romans 2:28–29; Romans 4:11–12).