Jeremiah 31:26 - Ellicott's Commentary On The Whole Bible

Upon this I awaked... — The words that follow have been very differently interpreted. By some writers (Rosenmüller) they have been referred to Jehovah under the figure of the husband who has dreamt of his wife’s return. Others (Ewald) have seen in them a quotation from some well-known psalm or hymn, like Psalms 17:15, indicating that in the golden days to which Jeremiah looked forward there should be freedom even from the evil and dark dreams of a time of peril, so that every man should be able to give thanks for the “sweet” gift of sleep (Psalms 127:2). It is, however, far more natural to take them as the prophet’s own words. The vision of a restored Israel, such as he paints it in the preceding verses, had come to him in his sleep. (See Jeremiah 23:28; Joel 2:28, as to this mode of revelation.) And when he woke up there was no sense of bitter disappointment like that of the dreamer described in Isaiah 29:8. The promise that came to him when he woke was as distinct and blessed as the dream had been. The “sweet sleep” has its parallel in Proverbs 3:24.