The Quran root ق س ط q-s-ṭ

شَهِدَ اللَّهُ أَنَّهُ لَا إِلَٰهَ إِلَّا هُوَ وَالْمَلَائِكَةُ وَأُولُو الْعِلْمِ قَائِمًا بِالْقِسْطِ لَا إِلَٰهَ إِلَّا هُوَ الْعَزِيزُ الْحَكِيمُ ١٨

بِالْقِسْطِ bil-qis'ṭi · in justice

Allāh witnesses that there is no deity except Him, and [so do] the angels and those of knowledge - [that He is] maintaining [creation] in justice. There is no deity except Him, the Exalted in Might, the Wise. (Surah Ali 'Imran, 3:18)

إِنَّ الَّذِينَ يَكْفُرُونَ بِآيَاتِ اللَّهِ وَيَقْتُلُونَ النَّبِيِّينَ بِغَيْرِ حَقٍّ وَيَقْتُلُونَ الَّذِينَ يَأْمُرُونَ بِالْقِسْطِ مِنَ النَّاسِ فَبَشِّرْهُم بِعَذَابٍ أَلِيمٍ ٢١

بِالْقِسْطِ bil-qis'ṭi · [with] justice

Those who disbelieve in the signs of Allāh and kill the prophets without right and kill those who order justice from among the people - give them tidings of a painful punishment. (Surah Ali 'Imran, 3:21)

وَإِنْ خِفْتُمْ أَلَّا تُقْسِطُوا فِي الْيَتَامَىٰ فَانكِحُوا مَا طَابَ لَكُم مِّنَ النِّسَاءِ مَثْنَىٰ وَثُلَاثَ وَرُبَاعَ فَإِنْ خِفْتُمْ أَلَّا تَعْدِلُوا فَوَاحِدَةً أَوْ مَا مَلَكَتْ أَيْمَانُكُمْ ذَٰلِكَ أَدْنَىٰ أَلَّا تَعُولُوا ٣

تُقْسِطُوا tuq'siṭū · you will be able to do justice

And if you fear that you will not deal justly with the orphan girls, then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one or those your right hands possess [i.e., slaves]. That is more suitable that you may not incline [to injustice]. (Surah An-Nisa, 4:3)

سَمَّاعُونَ لِلْكَذِبِ أَكَّالُونَ لِلسُّحْتِ فَإِن جَاءُوكَ فَاحْكُم بَيْنَهُمْ أَوْ أَعْرِضْ عَنْهُمْ وَإِن تُعْرِضْ عَنْهُمْ فَلَن يَضُرُّوكَ شَيْئًا وَإِنْ حَكَمْتَ فَاحْكُم بَيْنَهُم بِالْقِسْطِ إِنَّ اللَّهَ يُحِبُّ الْمُقْسِطِينَ ٤٢

الْمُقْسِطِينَ l-muq'siṭīna · the ones who are just

[They are] avid listeners to falsehood, devourers of [what is] unlawful. So if they come to you, [O Muḥammad], judge between them or turn away from them. And if you turn away from them - never will they harm you at all. And if you judge, judge between them with justice. Indeed, Allāh loves those who act justly. (Surah Al-Ma'idah, 5:42)

يَا أَيُّهَا الَّذِينَ آمَنُوا إِذَا تَدَايَنتُم بِدَيْنٍ إِلَىٰ أَجَلٍ مُّسَمًّى فَاكْتُبُوهُ وَلْيَكْتُب بَّيْنَكُمْ كَاتِبٌ بِالْعَدْلِ وَلَا يَأْبَ كَاتِبٌ أَن يَكْتُبَ كَمَا عَلَّمَهُ اللَّهُ فَلْيَكْتُبْ وَلْيُمْلِلِ الَّذِي عَلَيْهِ الْحَقُّ وَلْيَتَّقِ اللَّهَ رَبَّهُ وَلَا يَبْخَسْ مِنْهُ شَيْئًا فَإِن كَانَ الَّذِي عَلَيْهِ الْحَقُّ سَفِيهًا أَوْ ضَعِيفًا أَوْ لَا يَسْتَطِيعُ أَن يُمِلَّ هُوَ فَلْيُمْلِلْ وَلِيُّهُ بِالْعَدْلِ وَاسْتَشْهِدُوا شَهِيدَيْنِ مِن رِّجَالِكُمْ فَإِن لَّمْ يَكُونَا رَجُلَيْنِ فَرَجُلٌ وَامْرَأَتَانِ مِمَّن تَرْضَوْنَ مِنَ الشُّهَدَاءِ أَن تَضِلَّ إِحْدَاهُمَا فَتُذَكِّرَ إِحْدَاهُمَا الْأُخْرَىٰ وَلَا يَأْبَ الشُّهَدَاءُ إِذَا مَا دُعُوا وَلَا تَسْأَمُوا أَن تَكْتُبُوهُ صَغِيرًا أَوْ كَبِيرًا إِلَىٰ أَجَلِهِ ذَٰلِكُمْ أَقْسَطُ عِندَ اللَّهِ وَأَقْوَمُ لِلشَّهَادَةِ وَأَدْنَىٰ أَلَّا تَرْتَابُوا إِلَّا أَن تَكُونَ تِجَارَةً حَاضِرَةً تُدِيرُونَهَا بَيْنَكُمْ فَلَيْسَ عَلَيْكُمْ جُنَاحٌ أَلَّا تَكْتُبُوهَا وَأَشْهِدُوا إِذَا تَبَايَعْتُمْ وَلَا يُضَارَّ كَاتِبٌ وَلَا شَهِيدٌ وَإِن تَفْعَلُوا فَإِنَّهُ فُسُوقٌ بِكُمْ وَاتَّقُوا اللَّهَ وَيُعَلِّمُكُمُ اللَّهُ وَاللَّهُ بِكُلِّ شَيْءٍ عَلِيمٌ ٢٨٢

أَقْسَطُ aqsaṭu · (is) more just

O you who have believed, when you contract a debt for a specified term, write it down. And let a scribe write [it] between you in justice. Let no scribe refuse to write as Allāh has taught him. So let him write and let the one who has the obligation [i.e., the debtor] dictate. And let him fear Allāh, his Lord, and not leave anything out of it. But if the one who has the obligation is of limited understanding or weak or unable to dictate himself, then let his guardian dictate in justice. And bring to witness two witnesses from among your men. And if there are not two men [available], then a man and two women from those whom you accept as witnesses - so that if one of them [i.e., the women] errs, then the other can remind her. And let not the witnesses refuse when they are called upon. And do not be [too] weary to write it, whether it is small or large, for its [specified] term. That is more just in the sight of Allāh and stronger as evidence and more likely to prevent doubt between you, except when it is an immediate transaction which you conduct among yourselves. For [then] there is no blame upon you if you do not write it. And take witnesses when you conclude a contract. Let no scribe be harmed or any witness. For if you do so, indeed, it is [grave] disobedience in you. And fear Allāh. And Allāh teaches you. And Allāh is Knowing of all things. (Surah Al-Baqarah, 2:282)

وَأَنَّا مِنَّا الْمُسْلِمُونَ وَمِنَّا الْقَاسِطُونَ فَمَنْ أَسْلَمَ فَأُولَٰئِكَ تَحَرَّوْا رَشَدًا ١٤

الْقَاسِطُونَ l-qāsiṭūna · (are) unjust

And among us are Muslims [in submission to Allāh], and among us are the unjust. And whoever has become Muslim - those have sought out the right course. (Surah Al-Jinn, 72:14)