فَهَزَمُوهُم بِإِذْنِ اللَّهِ وَقَتَلَ دَاوُودُ جَالُوتَ وَآتَاهُ اللَّهُ الْمُلْكَ وَالْحِكْمَةَ وَعَلَّمَهُ مِمَّا يَشَاءُ ۗ وَلَوْلَا دَفْعُ اللَّهِ النَّاسَ بَعْضَهُم بِبَعْضٍ لَّفَسَدَتِ الْأَرْضُ وَلَٰكِنَّ اللَّهَ ذُو فَضْلٍ عَلَى الْعَالَمِينَ (251)
(2:251) Consequently, by Allah's grace, they routed the unbelievers, and David killed Goliath; and Allah gave him kingship and wisdom and taught him whatever other things He willed. And if Allah had not been repelling one set of people by means of another, the earth *273 would have been filled with chaos. *274 But Allah is bountiful to the world (and so repels chaos in this way).
*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.