There are a number of difficulties in this verse. In general terms it is a warning against the arrogance and conceit of wicked people. It is a single statement that continues through the two lines of the verse.

“Haughty eyes and a proud heart”: The two qualities or attitudes here are literally “lifting up of eyes,” that is, “haughtiness” or “pride,” and “extensive of heart,” which is an idiomatic expression for “arrogance.” A number of versions reproduce the literal form of the expressions; examples of those that render the sense of the idioms are “conceit and arrogance” (Good News Translation) and “are proud and arrogant” (Contemporary English Version).

“The lamp of the wicked, are sin”: This line continues the statement begun in the first line. There are three problems to deal with in understanding the expression “the lamp of the wicked”.

(1) What is the meaning of the term translated “lamp” (nir in Hebrew)? The term nir can mean “plowing” or “fallow ground,” as it does in 13.23; or it can mean “lamp.” King James Version renders it “plowing” here, but most other versions that render it literally have “lamp.” The answer to the next question, however, may suggest that the term does not have to be rendered literally.
(2) What does the whole expression mean? Whether we understand “lamp” or “plowing,” the expression as a whole is figurative. If we understand “plowing,” this may be taken as an agricultural picture of the preparation for life or the way of living of the wicked person. If we understand nir as “lamp,” then the sense may be something like “the light that guides the life of the wicked person.” Contemporary English Version provides examples of both possibilities with “sin is the only crop they produce” in the text, and “sin is the only light they ever follow” in a footnote.
(3) How does this expression relate to the two expressions in the previous line? “The lamp” may be taken as summing up the first line, “their whole arrogant style of life,” which is labeled as “sin”. The punctuation of New Revised Standard Version, which places the expression “the lamp of the wicked” between dashes, shows that it takes this view. Revised English Bible “these sins brand the wicked” has a similar understanding.

(4) On the other hand, the expression may be taken as a third quality or attitude in addition to those in the first line. On this view the expression would be equivalent to something like “and all their outlook”; this would give a progression in the description of their values, from “pride and arrogance” to everything about the way they think or act.

There is more support among translations for the first of these two views, that is, taking “lamp” as summarizing or commenting on line 1. An example of a rendering that expresses it is, “People who do evil are big in the head and always arrogant, so sin fills up their life.”

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Proverbs. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .