Psalm 23:1–4: Prayer Walking Through the Valley
Psalm 23 does not promise that the valley is avoided, only that the shepherd is present in it. The psalm's comfort is companionship, not the removal of danger.
Psalm 23:1–4: God With Us in the Dark Valley
David does not promise that the valley is avoided or shortened. He says that God is with him in it, and that this is why he will not fear evil.