What is the meaning of the Almighty’s saying: "And We certainly gave David from Us bounty"?

Ibn Kathir clarifies that this verse speaks of Allah's blessings upon His Prophet David (peace be upon him) by combining prophethood and kingship, and by bestowing upon him a magnificent voice, with which mountains and birds would join in glorifying Allah. The Messenger of Allah (peace and blessings be upon him) praised Abu Musa al-Ash'ari, saying: "He has been given a mizmar (flute/melodious voice) from the mazamir of the family of David." Scholars have differed regarding the favor mentioned in the verse. Al-Shawkani cited several opinions, including: prophethood, the Psalms (Zabur), knowledge, strength, the subjugation of mountains, repentance, just rule, softening iron, and a beautiful voice. Al-Shawkani favored the opinion that the mentioned favor is what was subsequently mentioned, namely the subjugation of mountains.