Verse 9 is in the form of a proverbial statement, which is the basis for verse 10.

In Hebrew thought the heart was the instrument of reason, and not the seat of emotions, as it is for native speakers of English. Thus “human mind” is probably the best natural equivalent in English. Most translations retain “heart,” though Traduction œcuménique de la Bible has “thoughts.”

Deceitful can also be translated “devious,” or be rendered by a term that means “crooked” or “not straightforward.”

Above all things could mean either that the human mind is more devious than anything else is, or that its main characteristic is that it is devious. The first of these seems to be the best, as in “There is nothing else so deceitful” (Good News Translation). In some languages it is better to restructure this slightly, as in “The human mind is the most devious thing there is” or “The most devious thing of all is the human mind.”

The Hebrew word translated corrupt (New Jerusalem Bible “depraved”) may also mean “incurable” (see Isa 17.11 and Revised English Bible “desperately sick”). Most translations seem to prefer the meaning “deceitful” or “treacherous.” New Revised Standard Version has “perverse,” which is also good. If possible, translators should use two different words or expressions for deceitful and desperately corrupt, as in “The human mind is the most devious thing there is, completely perverse.”

The question who can understand it? may also be expressed as a statement: “No one can understand it” or “It is impossible to understand it.” Good News Translation found it better in English discourse to begin the verse with this rhetorical question.

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 .