For the morning is to them even as the shadow of death - They dread the light as one does usually the deepest darkness. The morning or light would reveal their deeds of wickedness, and they therefore avoid it.
As the shadow of death - As the deepest darkness; see the notes at Job 3:5.
If one know them - If they are recognized. Or, more probably, this means "they," that is, each one of them, "are familiar with the terrors of the shadow of death," or with the deepest darkness. By this rendering the common signification of the word (יכיר yakı̂yr) will be retained, and the translation will accord with the general sense of the passage. The meaning is, that they are familiar with the blackest night. They do not dread it. They dread only the light of day. To others the darkness is terrible; to them it is familiar. The word rendered "shadow of death" in the latter part of this verse, is the same as in the former. It may mean in both places the gloomy night that resembles the shadow, of death. Such a night is "terrible" to most people, to them it is familiar, and they feel secure only when its deep shades are round about them.

For the morning is to them even as the shadow of death,.... It is as disagreeable, and as hateful, and as terrible to them as the grossest and thickest darkness can be to others. The word is to be rendered either "alike" or "altogether", and not "even", as in our version: "the morning is to them equally" or "together" (w); that is, to the murderer, robber, thief, adulterer, and housebreaker, "as the shadow of death"; alike disagreeable to them all; or "the shadow of death is to them together" or "alike as the morning"; what the morning is to others, exceeding pleasant and delightful, that to them is the shadow of death, or the darkest night; they love darkness rather than light:
if one know them, they are in the terrors of the shadow of death; they are frightened unto death, they are in as great terror as a man is to whom death is the king of terrors; and who is sensible of the near approach of it, the plain and manifest symptoms of it being upon him: this is the case of the murderer, adulterer, and thief, when they are caught in the fact; or are known by such who are capable of giving notice of them, detecting them, and bearing witness against them: or "he", each and everyone of these, "knows the terrors of the shadow of death" (x); the darkest night, which strikes terrors into others, is known by them, is delighted in by them, is familiar with them, and friendly to them, and is as pleasing as the brightest day to others.
(w) Pariter, Pagninus, Montanus, &c. (x) "agnoscit terrores umbrae mortis", Mercerus, Cocceius; so Codurcus, Schmidt.

They shrink from the "morning" light, as much as other men do from the blackest darkness ("the shadow of death").
if one know--that is, recognize them. Rather, "They know well (are familiar with) the terrors of," &c. [UMBREIT]. Or, as MAURER, "They know the terrors of (this) darkness," namely, of morning, the light, which is as terrible to them as darkness ("the shadow of death") is to other men.

Is - Terrible and hateful.