Because - "For." Jeremiah returns to, and continues the words of, Jeremiah 18:13.

Vanity - A word meaning "falsehood," which signifies that the worship of idols is not merely useless but injurious.

They have caused them to stumble - Judah's prophets and priests were they who made her to err Jeremiah 5:31. The idols were of themselves powerless for good or evil.

In their ways ... - Or, "in their ways, the everlasting paths, to walk in byways, in a road not cast up. The paths of eternity" carry back the mind not to the immediate but to the distant past, and suggest the good old ways in which the patriarchs used to walk. The "road cast up" means one raised sufficiently to keep it out of the reach of floods etc.

Because my people hath forgotten me,.... Or, "that they have forgotten me" (z); this is the horrible thing they have done, which was unheard of among the Gentiles, who were always tenacious of their gods, and the worship of them; and that foolish and unwise thing, which was like leaving pure flowing streams of water for dirty puddles. This is to be understood of their forsaking the worship of God, as the Targum interprets it, and following after idols:

they have burnt incense to vanity; to idols, which are vain empty things, and which cannot give their worshippers what they expect from them: or, "in vain they burn incense" (a); even to the true God, while they also sacrificed unto idols; which to do was an abomination to the Lord, Isaiah 1:13; and especially burning incense to idols must be a vain thing; and so the Targum,

"to no profit a they burn incense or spices:''

and they have caused them to stumble in their ways; that is, either the idols they worshipped, or the false prophets caused the professing people of the Jews to stumble and fall in the ways into which they led them: and

from the ancient paths; or, "the paths of eternity" (b); which lead to eternal life; or which were of old marked out by the revealed will of God for the saints to walk in; and in which the patriarchs and people of God, in all former ages, did walk; and which were appointed from everlasting, and will remain for ever; and these are the good old paths in Jeremiah 6:16;

to walk in paths, in a way not cast up; a new way, unknown in former times; an unbeaten track, which the saints had never walked in; a rough path, unsafe and dangerous; and hence they stumbled, and fell, and came to ruin; as follows:

(z) "quod obliti sunt", Schmidt. (a) "frustra adolebunt, vel adolent", Pagninus, Calvin. (b) "semitae quae a seculo, seu antiquo", vid. Schmidt; so Targum; "semitis jam olim praescriptis", Piscator.

The application at Jeremiah 18:15 is introduced by a causal כּי. Ew. wrongly translates: that my people forgot me. כּי means for; and the causal import is founded on the main idea of Jeremiah 18:13 : A very horrible thing hath Israel done; for it hath done that which is unheard of in the natural world, it hath forsaken me, the rock of safety; cf. Jeremiah 2:32. They burn odours, i.e., kindle sacrifices, to the vanity, i.e., the null gods, cf. Psalm 31:7, i.e., to Baal, Jeremiah 7:9; Jeremiah 11:13, Jeremiah 11:17. The subject to יכשׁלוּם may be most simply supplied from the idea of "the vanity:" the null gods made them to stumble; cf. for this idea 2 Chronicles 28:23. This seems more natural than to leave the subject indefinite, in which case the false prophets (cf. Jeremiah 23:27) or the priests, or other seducers, would be the moving spirits. "The ancient paths" is apposition to "their ways:" upon their ways, the paths of the old time, i.e., not, however, the good old believing times, from whose ways the Israelites have but recently diverged. For עולם never denotes the time not very long passed away, but always old, immemorial time, here specially the time of the patriarchs, who walked on the right paths of faithfulness to God, as in Jeremiah 6:16. Hitz. and Graf have taken "the ancient paths" as subject: the old paths have made the Israelites to stumble on their ways, which gives a most unnatural idea, while the "paths of the earliest time" is weakened into "the example of their ancestors;" and besides, the parallelism is destroyed. As "by-paths" is defined by the apposition "a way not cast up," so is "on their ways" by "the ancient paths." The Chet. שׁבוּלי is found only here; the Keri is formed after Psalm 77:20. A way not cast up is one on which one cannot advance, reach the goal, or on which one suffers hurt and perishes. - In Jeremiah 18:16 the consequences of these doings are spoken of as having been wrought out by themselves, in order thus to bring out the God-ordained causal nexus between actions and their consequences. To make their land an object of horror to all that set foot on it. שׁרוּקות occurs only here, while the Keri שׁריקות is found only in Judges 5:16 for the piping of shepherds, from שׁרק, to hiss, to pipe. In connection with שׁמּה as expression of horror or amazement, Jeremiah elsewhere uses only שׁרקה, cf. Jeremiah 19:8; Jeremiah 25:9, Jeremiah 25:18; Jeremiah 29:18; Jeremiah 51:37, so that here the vowelling should perhaps be שׁרוּקת. The word does not here denote the hissing equals hissing down or against one, by way of contempt, but the sound midway between hissing and whistling which escapes one when one looks on something appalling. On "every one that passeth by shall be dismayed," cf. 1 Kings 9:8. הניע בּראשׁו only here equals הניע ראשׁ, to move the head to and fro, shake the head; a gesture of malicious amazement, cf. Psalm 22:8; Psalm 109:25, like מנוד ראשׁ, Psalm 44:15. - In Jeremiah 18:17 the Lord discloses the coming punishment. Like an east wind, i.e., a violent storm-wind (cf. Psalm 48:8), will I scatter them, cf. Jeremiah 13:24. Because they have turned to Him the back and not the face (cf. Jeremiah 2:27), so will He turn His back on them in the day of their ruin, cf. Ezekiel 35:5.

Because my people hath forgotten me, they have burned incense to vanity, and they have caused them to stumble in their ways from the {e} ancient paths, to walk in paths, in a way not cast up;

(e) That is, the way of truth which God had taught by his law, Jer 6:16.

18:15 Vanity - Idols. Ancient paths - The ways wherein Noah, Abraham, Isaac, and Jacob, and all the ancient patriarchs walked. To walk - In a way not cast up, not fit for God's people to walk in.

15. Because-rather, "And yet"; in defiance of the natural order of things.

forgotten me-(Jer 2:32). This implies a previous knowledge of God, whereas He was unknown to the Gentiles; the Jews' forgetting of God, therefore, arose from determined perversity.

they have caused . to stumble-namely the false prophets and idolatrous priests have.

ancient paths-(Jer 6:16): the paths which their pious ancestors trod. Not antiquity indiscriminately, but the example of the fathers who trod the right way, is here commended.

them-the Jews.

not cast up-not duly prepared: referring to the raised center of the road. Calvin translates, "not trodden." They had no precedent of former saints to induce them to devise for themselves a new worship.

18:11-17 Sinners call it liberty to live at large; whereas for a man to be a slave to his lusts, is the very worst slavery. They forsook God for idols. When men are parched with heat, and meet with cooling, refreshing streams, they use them. In these things men will not leave a certainty for an uncertainty; but Israel left the ancient paths appointed by the Divine law. They walked not in the highway, in which they might travel safely, but in a way in which they must stumble: such was the way of idolatry, and such is the way of iniquity. This made their land desolate, and themselves miserable. Calamities may be borne, if God smile upon us when under them; but if he is displeased, and refuses his help, we are undone. Multitudes forget the Lord and his Christ, and wander from the ancient paths, to walk in ways of their own devising. But what will they do in the day of judgment!