Charles Ellicott Commentary Jeremiah 18:15

"For my people have forgotten me, they have burned incense to false [gods]; and they have been made to stumble in their ways, in the ancient paths, to walk in bypaths, in a way not cast up;" — Jeremiah 18:15 (ASV)

Vanity. —The word is not that commonly so translated (Jeremiah 10:8; Ecclesiastes 1:2, et al., q. 5), but that which had been used of idols in Jeremiah 2:30; Jeremiah 4:30; Jeremiah 6:29, rendered “in vain.” See also Ezekiel 13:6; Ezekiel 13:8–9.

They have caused. —No persons have been named, but the prophet clearly has in view the prophets and teachers who had led the people astray.

To stumble in their ways from the ancient paths. —The preposition “from” is not in the Hebrew, and does not improve the sense. The words “the ancient paths,” literally, the paths of the age, or of eternity, are in apposition with “their ways,” and point to the old immemorial faith of the patriarchs, a faith not of today or yesterday. The second “paths” is a different word from the first, and implies rather the “by-ways,” as contrasted with the “way cast up,” the raised causeway, the “king’s highway,” on which a man could not easily lose his way.