Jer 18:4
18:4 And the vessel that he made of {a} clay was marred in the
     hand of the potter: so he made it again another vessel, as
     it seemed good to the potter to make [it].

     (a) As the potter has power over the clay to make what pot
         he will, or to break them, when he has made them: so
         have I power over you to do with you as seems good to
         me, Isa 45:9, Ro 9:20,21.

Jer 18:8
18:8 If that nation, against which I have pronounced, shall turn
     from their evil, I will {b} repent of the evil that I
     thought to do to them.

     (b) When the Scripture attributes repentance to God, it is
         not that he does contrary to that which he has ordained
         in his secret counsel: but when he threatens it is a
         calling to repentance, and when he gives man grace to
         repent, the threatening (which ever contains a
         condition in it) takes no place: and this the scripture
         calls repentance in God, because it so appears to man's
         judgment.

Jer 18:12
18:12 And they said, {c} There is no hope: but we will walk
      after our own plots, and we will every one do the
      imagination of his evil heart.

      (c) As men who had no remorse but were altogether bent to
          rebellion and to their own selfwill.

Jer 18:14
18:14 Will [a man] leave the snow of Lebanon [which cometh] from
      the rock of the field? {d} [or] shall the cold flowing
      waters that come from another place be forsaken?

      (d) As no man that has thirst refuses fresh waters which
          he has at home, to go and seek waters abroad to quench
          his thirst: so they should not seek help and comfort
          from strangers and leave God who was present with
          them.

Jer 18:15
18:15 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.

Jer 18:17
18:17 I will scatter them as with an east wind before the enemy;
      I will show them the back, and {f} not the face, in the
      day of their calamity.

      (f) I will show my anger and not my favour toward them.

Jer 18:18
18:18 Then said they, Come, and let us devise plots against
      Jeremiah; for the law {g} shall not perish from the
      priest, nor counsel from the wise, nor the word from the
      prophet. Come, and let us smite him with the {h} tongue,
      and let us not give heed to any of his words.

      (g) This argument the wicked have always used against the
          servants of God. The church cannot err: we are the
          Church, and therefore whoever speaks against us, they
          ought to die, 1Ki 22:24, Jer 7:4,20:2, Mal 2:4
          and thus the false Church persecutes the true Church,
          which stands not in outward pomp, and in multitude,
          but is known by the graces of the Holy Spirit.
      (h) Let us slander him and accuse him: for we will be
          believed.

Jer 18:21
18:21 Therefore {i} deliver their children to the famine, and
      pour out their [blood] by the force of the sword; and let
      their wives be bereaved of their children, and [be]
      widows; and let their men be put to death; [let] their
      young men [be] slain by the sword in battle.

      (i) Seeing the obstinate malice of the adversaries, who
          grew daily more and more, the prophet being moved with
          God's Spirit, without any carnal affection prays for
          their destruction because he knew that it would be to
          God's glory, and profit of his Church.