Jeremiah 31:36 - Matthew Poole's English Annotations on the Holy Bible

There are ordinances of worship, which are God's laws relating to his worship; and ordinances of justice, which are God's laws for the executing civil justice; and ordinances of nature, which are God's establishments for the working of natural causes in their order; these are those here spoken of, which shall hold and continue to the dissolution of the world, the continuance of which God pawneth as a pledge of the continuance of Israel as a nation all the days, (so it is in the Hebrew,) that is, many days, or all the days they shall keep close with him, or which he hath appointed. If we interpret it (as in our version) for ever, it must be understood not of Israel according to the flesh, but of the church, the true Israel of God, which shall never fail.