through. Not into; but "through", and out of it, into resurrection life.
valley, &c. = a valley of deep shade: may include (but not necessarily) death's dark valley.
evil. Hebrew. ra'a'.App-44.
Thou art with me. JEHOVAH-SHAMMAH. App-4.
rod and . . . staff = club and . . . crook. The only two things carried by the shepherd; the former for defense, the latter for help. The club for the sheep's enemies, the crook for the sheep's defense. A lesson for pastors to-day.
comfort = gently lead. Same word as "leadeth" in Psa_23:2.