What is the valley of the shadow of death?

The Hebrew phrase behind the shadow of death is tsalmaveth, and translations differ between the valley of the shadow of death and the darkest valley. Both are defensible, and the difference matters less than it appears. Either way the picture is a ravine where the light does not reach and the traveller cannot see far ahead.

So the verse is wider than a deathbed. It covers dying, and it also covers any stretch of life you have to walk through without being able to see the end of it. David does not tell us which valley he had in mind, and the psalm is more useful because he does not.

The verb is walking through. The valley is a passage, not a residence. That is a small word doing heavy work, because when you are inside a dark stretch it feels permanent, and the psalm quietly refuses that feeling without pretending the darkness is not real.

Notice also what David does not say. He does not say there is no evil. He says I will fear no evil, and he gives one reason for it: for you are with me. The absence of fear rests on presence, not on improved circumstances. Nothing in the verse suggests the valley got shorter or the shadow got lighter.

This is the most important thing in the verse and the easiest to miss. For three verses David has been speaking about the LORD in the third person, the way we speak about God when things are steady. In the valley the grammar changes and he speaks to Him.

That is what faith often looks like in the dark. Not a stronger argument for God's goodness, but a shift from talking about Him to talking to Him. If you are in a valley now and cannot manage a doctrine, the psalm shows you a shorter sentence: you are with me.