Indeed We have sent Our Messengers with clear proofs, and revealed with them the Scripture and the Mizan that mankind may keep up justice. And We brought forth iron wherein is mighty power, as well as many benefits for mankind, that Allah may test who it is that will help Him (His religion) and His Messengers in the unseen. Verily, Allah is Powerful, Almighty (25)

The Prophets were given Miracles and Sent with truth and Justice

Allah the Exalted said next,

لَقَدْ أَرْسَلْنَا رُسُلَنَا بِالْبَيِّنَاتِ

(Indeed We have sent Our Messengers with clear proofs) in reference to the miracles, the unequivocal evidences and the plain proofs,

وَأَنْزَلْنَا مَعَهُمُ الْكِتَابَ

(and revealed with them the Scripture) which contains the true text,

وَالْمِيزَانَ

(and the Mizan), that is, justice, according to Mujahid, Qatadah and others. This Ayah refers to the truth that is attested to by the sound, straight minds that oppose misguided opinions and ideas, just as Allah said in other Ayat,

أَفَمَنْ كَانَ عَلَىٰ بَيِّنَةٍ مِنْ رَبِّهِ وَيَتْلُوهُ شَاهِدٌ مِنْهُ

(Can they (Muslims) who rely on a clear proof from their Lord, and whom a witness from Him follows it (be equal with the disbelievers).)(11:17),

 فِطْرَتَ اللَّهِ الَّتِي فَطَرَ النَّاسَ عَلَيْهَا ۚ

(Allah's Fitra (religion) with which He has created mankind.)(30:30), and,

وَالسَّمَاءَ رَفَعَهَا وَوَضَعَ الْمِيزَانَ 

(And the heaven: He has raised it high, and He has set up the Mizan.)(55:7) This is why Allah said here,

 لِيَقُومَ النَّاسُ بِالْقِسْطِ

(that mankind may keep up justice), truth and fairness that is found in the obedience of the Messengers, in all that they conveyed from their Lord, and following all they commanded. Surely, what the Prophets brought forth is the truth, beyond which there is no truth, just as Allah said,

وَتَمَّتْ كَلِمَتُ رَبِّكَ صِدْقًا وَعَدْلًا ۚ 

(And the Word of your Lord has been fulfilled in truth and in justice.)(6:115), His Word is true in what it conveys, and just in all its orders and prohibitions. This is why the believers say, when they take up their rooms in Paradise and assume their high grades and lined thrones,

الْحَمْدُ لِلَّهِ الَّذِي هَدَانَا لِهَٰذَا وَمَا كُنَّا لِنَهْتَدِيَ لَوْلَا أَنْ هَدَانَا اللَّهُ ۖ لَقَدْ جَاءَتْ رُسُلُ رَبِّنَا بِالْحَقِّ ۖ 

(All praise is due to Allah, Who has guided us to this, and never could we have found guidance, were it not that Allah had guided us! Indeed, the Messengers of our Lord did come with the truth.)(7:43)

The Benefits of Iron

Allah said,

وَأَنْزَلْنَا الْحَدِيدَ فِيهِ بَأْسٌ شَدِيدٌ

(And We brought forth iron wherein is mighty power,) meaning, 'We made iron a deterrent for those who refuse the truth and oppose it after the proof has been established against them.'

Allah's Messenger ﷺ remained in Makkah for thirteen years. During that time, the revelation continued being sent to him, containing arguments against the idolators and explaining Tawhid with detail and proofs. When the evidence was established against those who defied the Messenger ﷺ, Allah decreed the Hijrah. Then He ordered the believers to fight the disbelievers using swords, using them to strike the necks and foreheads of those who opposed, rejected and denied the Qur'an. Imam Ahmad and Abu Dawud recorded that 'Abdullah bin 'Umar said that the Messenger of Allah ﷺ said,

بُعِثْتُ بِالسَّيْفِ بَيْنَ يَدَيِ السَّاعَةِ حَتّٰى يُعْبَدَ اللهُ وَحْدَهُ لَا شَرِيكَ لَهُ، وَجُعِلَ رِزْقِي تَحْتَ ظِلِّ رُمْحِي، وَجُعِلَ الذِّلَّةُ والصَّغَارُ عَلَىٰ مَنْ خَالَفَ أَمْرِي، وَمَنْ تَشَبَّهَ بِقَوْمٍ فَهُوَ مِنْهُمْ

(I was sent with the sword just before the Hour so that Allah be worshipped alone without partners. My provision was placed under the shadow of my spear, and those who defy my order were disgraced and humiliated, and he who imitates a people is one of them.) This is why Allah the Exalted said,

فِيهِ بَأْسٌ شَدِيدٌ

(wherein is mighty power,) in reference to weapons, such as swords, spears, daggers, arrows, shields, and so forth,

وَمَنَافِعُ لِلنَّاسِ 

(as well as many benefits for mankind,) meaning, in their livelihood, such as using it to make coins, hammers, axes, saws chisels, shovels and various tools that people use for tilting the land, sowing, cooking, making dough and manufacturing other objects necessary for their livelihood. Allah's statement,

وَلِيَعْلَمَ اللَّهُ مَنْ يَنْصُرُهُ وَرُسُلَهُ بِالْغَيْبِ

(that Allah may test who it is that will help Him (His religion) and His Messengers in the unseen.) meaning, whose intention by carrying weapons is the defense of Allah (His religion) and His Messenger,

إِنَّ اللَّهَ قَوِيٌّ عَزِيزٌ

(Verily, Allah is Powerful, Almighty.) meaning, surely, Allah is Powerful, Almighty, and He gives victory to those who give victory and aid to Him. However, Allah does not need mankind's help, but He ordered Jihad to test people with each other.