Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(If ye have received a blow) if you were harmed on the Day of Uhud, (the (disbelieving) people) the people of Mecca (have received) on the Day of Badr (a blow) harm (the like thereof) like the harm you received on the Day of Uhud: (These are (only) the vicissitudes) the days of the life of this world (which We cause to follow one another for mankind) sometimes the believers have the upper hand over the unbelievers and sometimes it is the unbelievers who have the upper hand over the believers, (to the end that Allah may know) that He may see (those who believe) at the time of jihad (and may choose witnesses from among you) He honours whom He wills among you with martyrdom; (and Allah loveth not wrong-doers) He loves not the idolaters, their religion or their domination.
If a wound touches you, befalls you at Uhud, a like wound (qarh or qurh, which is the exhaustion that results from a wound and the like), already, at Badr, has touched the other people, the disbelievers. Such days We deal out in turn, We dispense them, among mankind, one day for one group, the next day for another, that they might be admonished, and that God may know, through knowledge manifested outwardly, those who believe, who are sincere in their faith from others; and that He may take witnesses from among you, honouring them with martyrdom, and God loves not the evildoers, the disbelievers, that is, He will chastise them, and the blessings He bestows upon them are only a [means of] drawing out [their punishment].
[Such] days: [such] events. Any tremendous affair that occurs is called 'a day' or 'days', as [in the expression] where God says And remind them of the Days of God [Q. 14:5]. The explanation of 'that God may know' has already been given to mean the manifestation of knowledge at the level of differentiation that is subsequent to the eventuality of known things; and that He may take witnesses from among you, those who bear witness to the Truth such that they are distracted from their souls. In other words, We deal out [such] events among mankind for various purposes and [on the basis of] many wisdoms which are not mentioned, from [allowing for] the actualisation of what [potential] is [contained] in their preparedness, to action in the way of patience, endurance, the strength of certainty and little concern for the soul, its being mastered and suppressed by the heart and so on; and also for the two reasons mentioned [in the verse] and to deliver the believers from sins and coverings that distance them from God through punishment and trial, when these [days] are against them; and to obliterate the disbelievers, to vanquish them and destroy them when these [days] are in their favour. Between the reasons given [by God] comes a parenthetical: and God loves not the evildoers, in order that it be known that the one who lacks the attribute of faith and witnessing, as well as [the capacity] to examine [his] sins and [lacks] the strength of steadfastness to perfect [his] certainty, but is present at the battle in pursuit of spoils or for some other purpose, such a person is an evildoer and that God does not love him.
The Wisdom Behind the Losses Muslims Suffered During Uhud
Allah states to His believing servants who suffered losses in the battle of Uhud, including seventy dead,
قَدْ خَلَتْ مِن قَبْلِكُمْ سُنَنٌ
(137... Many similar ways (and mishaps of life) were faced before you), for the previous nations who followed their Prophets before you, they too suffered losses. However, the good end was theirs, and the ultimate defeat was for the disbelievers. This is why Allah said,
(And Allah likes not the wrongdoers. And that Allah may test those who believe) 3:140,141, by forgiving them their sins if they have any. Otherwise, Allah will raise their grades according to the losses they suffered. Allah's statement,
(and destroy the disbelievers), for it is their conduct that if they gain the upper hand, they transgress and commit aggression. However, this conduct only leads to ultimate destruction, extermination, perishing and dying out...(3:141 end...)
(Or think you that you will enter Paradise without such (trials) as came to those who passed away before you They were afflicted with severe poverty and ailments and were so shaken...) 2:214. Allah said,
(Do you think that you will enter Paradise before Allah knows (tests) those of you who will perform Jihad and (also) knows (tests) those who are the patient) 3:142 meaning, you will not earn Paradise until you are tested and thus Allah knows who among you are the ones who struggle and fight in His cause and are patient in the face of the enemy. Allah said,
(Do not wish to encounter the enemy, and ask Allah for your well-being. However, if you do encounter them, then observe patience and know that Paradise is under the shade of swords.)
This is why Allah said here,
(Now you have seen it): death, you saw it when the swords appeared, the blades were sharpened, the spears crisscrossed and men stood in lines for battle. This part of the Ayah contains a figure of speech that mentions imagining what can be felt but not seen.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
God is encouraging the Muslims by mentioning the victory in the battle of Badr, saying, "When the disbelievers did not lose heart by the blow at Badr, why should you, the believers, lose heart by the blow at Uhd?"
The original Arabic text may imply either of the two things: "Allah desired to give some of you the honour of martyrdom. " Or it may mean, "He willed to winnow the Believers from the hypocrites so that the true witnesses of the Truth, who may really be worthy of performing the mission that has been assigned to the Muslim Community, may be distinguished from the false ones."
This alludes to those who were so desirous of martyrdom that they had persuaded the Holy Prophet against his wish to go out of Al-Madinah to fight with the enemy.
If a wound touches you a like wound already has touched the other people. Such days We deal out in turn among mankind and that God may know those who believe; and that He may take witnesses from among you and God loves not the evildoers. “If a difficulty has come to you for Our sake they have faced something similar before you. They have been given something like what you have been given.” Those who are patient among them will be victorious fa-man ṣabara minhum ẓafira while those who suffer what comes with annoyance and anger will lose wa man Ḍajira min ḥamli ma laqiya khasira. Days come in turns al-ayām nuwabun and circumstances change wa-l-ḥālāt duwalun and nothing is hidden from the Real.
(If ye have received a blow, the (disbelieving) people have received a blow the like thereof) [3:140]. Said Rashid ibn Sa'd: “When the Messenger of Allah, Allah bless him and give him peace, returned from Uhud, sad and dejected, women whose husbands and sons were killed went to him crying and slapping their faces. Seeing this, the Messenger of Allah, Allah bless him and give him peace, exclaimed: 'Is this how Your Messenger is treated?' And Allah, exalted is He, revealed this verse (If ye have received a blow, the (disbelieving) people have received a blow the like thereof)”.