Tafsir of Al-Baqarah 2:251

(So they defeated them) means they routed them and overcame them. The Fa (So) here is Fasiha (eloquent/explanatory), implying that Allah the Exalted responded to their supplication; thus, they were patient, remained steadfast, were granted victory, and subsequently (defeated them by the permission of Allah), meaning by His will that they be defeated. This culminates in His victory and support. The Ba (in bi-idhnillahi) signifies either seeking aid and causality, or accompaniment.

(And David killed Goliath)—he is the son of Jesse. Regarding (Goliath), Abd al-Razzaq, Ibn Jarir, Ibn al-Mundhir, and Ibn Abi Hatim recorded from Wahb ibn Munabbih that he said: When Saul confronted Goliath, Goliath said, "Bring forth someone to fight me. If he kills me, then you have my kingdom, and if I kill him, I have your kingdom." David was brought to Saul, who made a pact with him that if he killed him, he would marry him to his daughter and grant him authority over his wealth. Saul clothed him in armor, but David disliked fighting with it, saying, "If Allah the Exalted does not grant me victory over him, the armor will be of no avail." He went out to him with a sling and a pouch containing stones. When he confronted him, Goliath said, "Are you the one fighting me?" David said, "Yes." He said, "Woe to you! Have you come out against me as one would come out against a dog—with a sling and stones? I will scatter your flesh and feed it today to the birds and the beasts of prey." David said to him, "Rather, you are an enemy of Allah the Exalted, worse than a dog." David took a stone, threw it with the sling, and it struck him between the eyes until it lodged in his brain. Goliath shrieked, his companions fled, and David cut off his head.

(And Allah gave him the kingdom)—among the Children of Israel, after he killed Goliath and Saul perished. The account is that when Saul returned, as narrated in some traditions, he fulfilled the condition, married his daughter to David, and allowed his signet ring to be used in his kingdom. The people gravitated toward David and loved him. When Saul saw this, he felt resentment and envied him, so he sought to kill him. David learned of this, so he placed a wineskin in his sleeping place. Saul entered David's sleeping quarters while David had fled, struck the skin a blow, and pierced it; wine flowed out, and Saul said, "May Allah have mercy on David; how great was his consumption of wine!" Subsequently, David came to him the next night while he was asleep in his house and placed two arrows by his head, two by his feet, two to his right, and two to his left. When Saul awoke, he saw the arrows and recognized them, saying, "May Allah have mercy on David; he is better than I. I had power over him and killed him [in intent], but he had power over me and spared me."

Then, one day, Saul rode out and found David walking in the wilderness while Saul was on a horse. He said, "Today I shall kill David," and David was known for being impossible to catch when he fled. Saul galloped in his pursuit, and David, in fear, ran hard and entered a cave. Allah the Exalted revealed to a spider, and it spun a web over it. When Saul reached the cave and looked at the spider's web, he said, "If he had entered here, he would have torn the spider's web." So he returned. The scholars and worshippers began to criticize him for what he did to David, and he began killing the scholars and anyone who forbade him from killing David until he killed many people. Then, he repented thereafter, abandoned the kingdom, and having ten sons, he took them and went out to fight in the way of Allah the Exalted as an expiation for what he had done, until he and his sons were killed in the way of Allah the Exalted. Thus, the Children of Israel gathered around David and installed him as their ruler. This is the giving of the kingdom.

(And wisdom)—the intent by this is prophecy. Before him, kingdom and prophecy were never combined in one person; rather, prophecy was in one tribe and kingdom in another. This occurred after the death of that prophet, and his death was before Saul. Wisdom is mentioned after kingdom because its occurrence was subsequent, or to ascend from the mention of the lower to the higher.

(And He taught him of what He wills)—such as the craft of making armor, the language of birds, and the speech of beasts. The hidden pronoun refers to Allah the Exalted. The view that it returns to David, as stated by al-Samin, is weak, for most of what Allah taught him is something that would hardly cross the mind or occur in the wishes of a human, so that he might be enabled to ask for it or will it.

(And if it were not for Allah's repelling of people, some of them)—who are the people of evil in the world, in religion, or in both—(by others)—another group among them who restrain them from what they are upon by what Allah has decreed of killing, as in the related story, or otherwise. Nafi‘ read here and in [Surah] al-Hajj as dif‘ (repressing) on the basis that the form of mutual struggle signifies intensification.

(The earth would have been corrupted)—its benefits would have been voided, and its interests—regarding tillage, offspring, and all that improves and develops the earth—would have been paralyzed. It is also said that it is a metonymy for the corruption of its people and the prevalence of evil among them. In this is an indication of the virtue of kingship and that without it, the order of the world would not be established. Thus it is said: "Religion and kingship are twins; the elevation of one is the elevation of the other," because religion is the foundation and kingship is the guardian. That which has no foundation is demolished, and that which has no guardian is lost.

(But Allah is full of bounty)—that cannot be estimated—(upon the worlds)—entirely. This is an indication of a conditional syllogism composed of the positing of the contradictory of the antecedent to yield the contradictory of the consequent, except that He placed in its stead that which entails and necessitates it, namely His being—the Exalted—(full of bounty upon the worlds). This is to signify that He the Exalted bestows bounty in that repelling without it being obligatory upon Him, and that His bounty is not limited to that; rather, it is one of the manifestations of His immense bounty. It is as if it were said: "But He, the Exalted, repels the corruption of some by others, so the earth is not corrupted, and by this, the interests of the world are organized and the conditions of nations are rectified." This was stated by our master, the Mufti of the Ottoman lands, may his secret be sanctified.

It was objected that this contradicts the logicians' view that a conditional proposition only yields the consequent upon the affirmation of its antecedent, or the negation of the antecedent upon the negation of the consequent, because the existence of the malzum (necessitant) necessitates the existence of the lazim (necessitated), and the non-existence of the lazim necessitates the non-existence of the malzum. It does not invert; thus, the affirmation of the consequent does not yield the affirmation of the antecedent, nor does the negation of the antecedent yield the negation of the consequent, because the consequent may be more general than the antecedent. It was answered that this is only with regard to the formal structure, and it may be necessitated by the specificity of the material equality. Ibn Sina explicitly stated in the Fusus that if the entailment is from both sides—as is the case between cause and effect—the affirmation of each of the antecedent and consequent yields the affirmation of the other, and the negation of each yields the negation of the other. The people’s reasoning also contains an indication of this, as they said: "because the consequent may be more general." It seems the expression of the Master (Al-Alusi) contains an indication that the entailment in the conditional is from both sides, as he said: "yields" (in the active, muntijan) and did not say "it is yielded" (yuntaju).

Some answered that this statement of theirs is not universal, but applies when the negation of the antecedent is more general than the negation of the consequent. As for when the negation is the reverse of this, as in this noble verse and its like, it does yield the consequent. This is because since the mentioned repelling was the malzum for the lack of corruption of the earth, the entailment was established between them, for the existence of the malzum necessitates the existence of the lazim, as has been explained in its place. The claim that the entailment is from both sides here, as the first responder supposed, is unfounded; rather, the lazim here is more general than the malzum, as is not hidden from one of insight. That the Master's expression indicates that the entailment is from both sides is a point of contention, and what he mentioned does not prove it, as is not hidden. So understand and reflect, for the gaze of the Master is subtle.