For neighbor see verse 4.
They commit iniquity and are too weary to repent translates a difficult Hebrew text. However, as Hebrew Old Testament Text Project indicates, the problem may be resolved if the following steps are taken:
(1) the verb are too weary should here be given the meaning “are unable to”;
(2) they commit iniquity is best understood as a noun (“iniquity”), in apposition with and equivalent to lies;
(3) the letters of the Hebrew text should be redivided so that the noun “your dwelling” (Revised Standard Version footnote) results in “[they are unable to] come back. Oppression….” In this way “oppression” would belong to what follows in verse 6: “Oppression upon oppression….”
If these suggestions are followed, the Hebrew may be expressed as follows for lines 3-4: “They have taught their tongues to lie and to be dishonest. They will not quit sinning.”
They have taught their tongues to lie may need to be expressed as “they lie all the time” or “they are skilled liars.”
The Hebrew noun phrases oppression upon oppression and deceit upon deceit are translated as verb constructions by Good News Translation: “They do one violent thing after another, and one deceitful act follows another.” In many languages it may be preferable to say “They commit one oppressive act after another, and they do one deceitful thing after another” or “Time and time again they oppress other people and deceive them.”
Deceit is first used in 5.27, where Revised Standard Version has “treachery”; it will occur once again in verse 8. The same combination of the two nouns oppression and deceit appears in Psa 10.7; 55.11.
They refuse to know me is a slightly stronger statement than “they do not know me” in verse 3. Accordingly, we may translate “they refuse to acknowledge me as their God” or “… to obey me as their God.”
For says the LORD, see 1.8.
Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on Jeremiah. (UBS Helps for Translators). New York: UBS, 2003. For this and other handbooks for translators see here .