² With that in mind, we can understand the gravity of a situation described by the prophet Isaiah. He said: “Look! darkness itself will cover the earth, and thick gloom the national groups.” (Isaiah 60:2) Of course, this does not refer to darkness in a physical sense. Isaiah did not mean that some day the sun, moon, and stars would cease to shine. (Psalm 89:36, 37; 136:7-9) Rather, he was talking of spiritual darkness. But spiritual darkness is death dealing. In the long run, we cannot live without spiritual light any more than we can live without physical light.​—Luke 1:79.

3. In view of Isaiah’s words, what should Christians do?

³ In view of this, it is of serious concern to note that Isaiah’s words, although fulfilled on ancient Judah, are having a greater fulfillment today. Yes, in our time the world is shrouded in spiritual darkness. In such a dangerous situation, spiritual light is of the utmost importance.

4. When were Isaiah’s prophetic words first fulfilled, but what situation already existed in his own day?

⁴ Isaiah’s words about darkness covering the earth were first fulfilled when Judah lay desolate and her people were in exile in Babylon.