(Saba'a) 34 : 10
وَلَقَدْ آتَيْنَا دَاوُودَ مِنَّا فَضْلًا ۖ يَا جِبَالُ أَوِّبِي مَعَهُ وَالطَّيْرَ ۖ وَأَلَنَّا لَهُ الْحَدِيدَ
And surely We have bestowed Dawood Bounty from Us; Oh mountains! You turn into Me with him, as well as the birds, and We softened iron for him.
The Bounty given to Dawood is the Book Psalm (Zabur). It was in the form of rhyme. When Messenger Dawood recited It every morning and evening, the mountains echoed It and the birds by flapping their wings participated in it. See explanation 27: 15; 38: 17-20.