Tafheem ul Quran

Surah 2 Al-Baqarah, Ayat 251-251

فَهَزَمُوۡهُمۡ بِاِذۡنِ اللّٰهِ ۙ وَقَتَلَ دَاوٗدُ جَالُوۡتَ وَاٰتٰٮهُ اللّٰهُ الۡمُلۡكَ وَالۡحِکۡمَةَ وَعَلَّمَهٗ مِمَّا يَشَآءُ ​ؕ وَلَوۡلَا دَفۡعُ اللّٰهِ النَّاسَ بَعۡضَهُمۡ بِبَعۡضٍ لَّفَسَدَتِ الۡاَرۡضُ وَلٰـکِنَّ اللّٰهَ ذُوۡ فَضۡلٍ عَلَى الۡعٰلَمِيۡنَ‏ ﴿2:251﴾

(2:251) Thereupon by Allah’s leave they put the unbelievers to flight, and David killed Goliath,273 and Allah granted him dominion and wisdom, and imparted to him the knowledge of whatever He willed. And were it not that Allah repelled some people with another, the earth would surely be overlaid with mischief.274 But Allah is Bounteous to the people of the world (and thus extirpates mischief).

Notes

273. David was then in the early years of his youth. By chance he joined the army of Saul just when the mighty champion of the Philistine army had challenged the Israelite army to combat. None of the Israelites had the courage to take up the challenge. On seeing this, David took on Goliath in a duel and slew him. From then on, David could do no wrong in the eyes of the Israelites. Saul gave him the hand of his daughter in marriage and ultimately he became the ruler of the Israelites. (For details see 1 Samuel, chapters 17 and I8.)

274. This enunciates the principle according to which God treats the nations as a part of the Divine system governing the world. He allows various nations to attain power and strength within certain limits. But when any nation begins to commit wrongs and exceed reasonable limits. God brings forth another nation as a counterweight, Were the dominion of one nation or party to endure for ever, and were its capacity to perpetrate wrongs granted in perpetuity, God's earth would become full of corruption and wickedness.