(So they routed them by Allah's leave) by Allah's help (and David) the Prophet (slew Goliath) the unbeliever; (and Allah gave him the kingdom) Allah gave David sovereignty over the Children of Israel (and wisdom) understanding and prophethood, (and taught him of that which He willeth) i.e. how to make armour. (And if Allah had not repelled some men by others) as He repelled through David the evil of Goliath from the Children of Israel (the earth would have been corrupted). He says: Allah repelled from the believers, by means of the prophets, the evil of their enemies, and He repelled from those who refrained from participating in the fight for Allah's sake, by means of those who fought in His sake, the evil of their enemies. If it were not thus, the earth would have been corrupted. (But Allah is a Lord of Kindness to all the worlds) by this repelling.