The proper words for prophecy. It is to be called an answer when the people have come to inquire of Yahweh: but His word when it is sent unasked.
Matthew Henry
Concise Bible Commentary
Those are miserable indeed who are forsaken and forgotten of God; and men's jesting at God's judgments will not baffle them. God had taken Israel to be a people near to him, but they shall now be cast out of his presence. It is a mark of great and daring impiety for men to jest with the words of God. Every idle and profane word will add to the sinner's burden in the day of judgment, when everlasting shame will be his portion.
SDA Bible Commentary (limited)
Volume 1-7
35. What hath the Lord answered? Evidently a protest against the daringly ungodly use of the words “the burden of the Lord” (v.34). Rejecting such deceptive teaching, Jeremiah appeals to the people to believe the true expressions of the divine will, which are the true answer to Judah’s problems and difficulties.