The teaching that Jesus mentions in this passage has become a rhyme related to sailors: “Red sky at night, sailor’s delight. Red sky at morning, sailors’ warning.” The sky appears red when the sun, at morning or evening, shines through clouds—the water particles in the clouds break up the light rays so that we see an orange-red glow.

As storms in the region tended to move from east to west, seeing the red light from clouds in the east meant that a storm was coming toward you, and seeing it in the west meant that it was moving away. Though they have much more sophisticated tools today, a red sky can still mean a lot to seafarers.

At the beginning of Matthew 16, we read that the religious leaders came to test Jesus by asking for a sign from heaven. This question is surprising since it came soon after Jesus’ miracle of feeding a huge crowd of “four thousand men, besides women and children” (Matthew 15:38). Was that not enough of a sign?

Jesus’ miracles were signs of the kingdom of God coming near (Mark 1:15), but few people were reading those signs. So Jesus hinted that his critics should take note of this. But they were stubborn and would not open their eyes. What was coming—in some ways like a storm—was good news: the Son of God, Jesus himself, had come to die for everyone’s sin so that all who believe in him could be saved.