Ar-Rad ('The Thunder'), 43 verses whose Meccan or Medinan placement is disputed, takes its name from the thunder that 'glorifies God with praise' (13:13). It marshals the wonders of creation, the raised heavens, alternating day and night, rain and growth, as evidence of the one Sustainer, and contrasts the restful heart of the believer with the denial of the obstinate.
Ar-Rad's disputed classification, Meccan in most catalogues but held Medinan by some early authorities including a report attributed to Ibn Abbas, is often explained by commentators as reflecting its mixed content, cosmological argument typical of the Meccan surahs alongside legal and covenantal language more characteristic of Medina. A widely transmitted account holds that thunder is the voice of an angel tasked with driving the clouds, a folk cosmology preserved in exegetical works such as al-Qurtubi's rather than stated directly in the Quranic text itself, which simply describes thunder as glorifying God alongside the angels who stand in awe of Him (13:13). The surah's image of the good word as a tree with firm roots and branches reaching the sky (13:24, closely paralleled in Ibrahim's tree at 14:24) is read by commentators as one of the Quran's clearest extended metaphors, with classical exegesis identifying the tree variously as the believer's declaration of faith or as the palm tree specifically, prized in Arabian agriculture for its constant yield.