Why does the Qur'an call the sun a "blazing lamp" (sirājan wahhājā) in 78:13?

Answer

In 78:13 Allah says "and placed a blazing lamp" (wa-jaʿalnā sirājan wahhājā), which the commentators unanimously identify as the sun. Sirāj means a lamp or lantern—something that gives light by its own burning—and wahhāj intensifies this to "blazing," combining brilliant light with intense heat. Ibn Kathīr explains that wahhāj joins both qualities together: radiant illumination and burning warmth. Al-Qurṭubī likewise notes the sun's combination of light and heat in this single word. The image works on two levels in the passage. First, it is a favour: the sun's light and warmth, together with the rain of the following verse, ripen the grain and gardens that sustain life. Al-Saʿdī notes the sun's heat is part of how God matures the earth's produce. Second, it is a sign pointing to resurrection—the larger argument of Surah An-Naba. It is also worth noting that the Qur'an consistently calls the sun a sirāj (a self-lit lamp) while calling the moon a nūr (reflected light), a consistent distinction in its vocabulary that the commentators recognized.