Passage
Thus saith Jehovah: If ye can break my covenant [in respect] of the day, and my covenant [in respect] of the night, so that there should not be day and night in their season,
Thus saith Jehovah: If ye can break my covenant [in respect] of the day, and my covenant [in respect] of the night, so that there should not be day and night in their season,
Jeremiah 33:18 neither shall there fail to the priests the Levites a man before me to offer up burnt-offerings, and to burn oblations, and to do sacrifice continually.
Jeremiah 33:19 And the word of Jehovah came to Jeremiah, saying,
Jeremiah 33:20 Thus saith Jehovah: If ye can break my covenant [in respect] of the day, and my covenant [in respect] of the night, so that there should not be day and night in their season,
Jeremiah 33:21 [then] shall also my covenant be broken with David my servant, that he should not have a son to reign upon his throne; and with the Levites, the priests, my ministers.
Jeremiah 33:22 As the host of the heavens cannot be numbered, nor the sand of the sea measured, so will I multiply the seed of David my servant, and the Levites that minister unto me.
The verse centers on "thus", "saith", "jehovah", "break", "covenant", and "respect". It is saying that the verse draws attention to "thus" and "saith", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 19's "And the word of Jehovah came to..." into verse 21's "then shall also my covenant be broken...", so "thus" and "saith" belong inside that flow. In Jeremiah context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "thus" and "saith" with trust shaped by these words, not by a vague optimism outside the passage.