21:79
To Solomon We inspired the (right) understanding of the matter: to each (of them) We gave Judgment and Knowledge; it was Our power that made the hills and the birds celebrate Our praises, with David: it was We Who did (all these things).
Commentators explain that the Qurʾānic verse describing the mountains glorifying God with David indicates that God granted David’s praises such power and beauty that the surrounding mountains responded in harmony with his glorification (cf. Qurʾān 21:79). In this interpretation, the mountains echoed and repeated David’s praises of God, creating a powerful and resonant expression of worship. The phenomenon is compared to natural echoes produced by mountainous landscapes, where sounds spoken toward a mountain are reflected back. According to this view, God enabled David to manifest this natural capacity of the mountains as a miracle, reflecting the special authority granted to him as both a prophet and a ruler.
Some commentators further suggest that this event demonstrates how elements of nature participate in the glorification of God. Mountains, possessing what is described metaphorically as a collective identity, are understood to offer forms of worship appropriate to their own nature. The echoing of human praise in mountainous terrain illustrates one way in which creation responds to divine glorification. In this interpretation, the Qurʾānic account also symbolically emphasizes that all aspects of creation—human beings and the natural world alike—participate in praising the Creator (Nursi, n.d., p. 271).
References:
Unal, Ali (2006). The Quran with Annotated Interpretation in Modern English. (surah 21verse 79)