23:4 shadow of death. This is not death, but the near danger of death. The phrase “shadow of death” occurs ten times in the book of Job (first in Job 3:5), four times in the Psalms, and four times in the prophetical books. The last occurrence is in Amos 5:8: “[He] turneth the shadow of death into the morning.”
23:4 comfort me. The application of the rod and the staff to the wandering sheep brings “comfort” in the sense of “causing repentance.” The same word is translated both ways. Note Hebrews 12:11.