zahar

In this sense the word pictures something that gives off light. Its one clear appearance is a promise that the wise will shine like the glow of the sky and like the stars forever (Daniel 12:3).

Scholars connect this bright picture to the word's far more common use, warning and teaching, through the idea of giving light: to shed light on a person is to enlighten, and so to instruct or caution them. Whether that makes shine and warn one word that stretched in meaning, or two separate words that happen to look alike, is debated. In this sense the plain meaning is simply to shine.

Most often this word means to warn. It is the language of an alarm: someone who sees the threat alerts another person to a danger or a duty so that person can respond in time. The clearest picture is the lookout, or watchman, in Ezekiel, who must warn the people that judgment is coming so they still have a chance to turn and live (Ezekiel 3:17 to 21; 33:1 to 9).

The same word also reaches toward teaching. To warn people about God's commands is, in effect, to instruct them in those commands, which is why one place uses it for teaching Israel the rules they must live by (Exodus 18:20).

It has a matching second side: to take a warning to heart. The watchman sounds the alarm; the hearer either heeds it and is saved or ignores it and bears the consequence (Ezekiel 33:4 to 6). This receiving sense also lies behind being cautioned or corrected by wise words (Ecclesiastes 4:13; 12:12).

Behind the whole range may stand the picture of giving light. To warn or to teach is, in a sense, to shed light on a danger or a duty so a person can see it clearly and choose well.