Tafsir Ibn Kathir (abridged)
Allah tells us that His servant and Messenger Dawud, peace be upon him, was endued with power
Al-Ayd means strength in knowledge and action. Ibn `Abbas, may Allah be pleased with him, As-Suddi and Ibn Zayd said, "Al-Ayd means strength." Mujahid said, "Al-Ayd means strength in obedience to Allah." Qatadah said, "Dawud, peace be upon him, was given strength in worship and the proper understanding of Islam." He told us that he, peace be upon him, used to spend a third of the night in prayer, and he fasted for half a lifetime. This was reported in the Two Sahihs, where it is recorded that the Messenger of Allah ﷺ said:
«أَحَبُّ الصَّلَاةِ إِلَى اللهِ تَعَالَى صَلَاةُ دَاوُدَ، وَأَحَبُّ الصِّيَامِ إِلَى اللهِ عَزَّ وَجَلَّ صِيَامُ دَاوُدَ، كَانَ يَنَامُ نِصْفَ اللَّيْلِ، وَيَقُومُ ثُلُثَهُ، وَيَنَامُ سُدُسَهُ، وَكَانَ يَصُومُ يَوْمًا وَيُفْطِرُ يَوْمًا، وَلَا يَفِرُّ إِذَا لَاقَى، وَأَنَّهُ كَانَ أَوَّابًا»
Continue reading the tafsir of ayahs 17–20