The Qur'ān says, “Indeed, God enjoins justice and kindness.” (16:90) Given that the context of this verse pertains to the responsibilities of human beings toward their society, the term ‘justice’ should be interpreted as ‘social justice’. Thus, God has ordered human beings to uphold justice.
'Allāma Ṭabāṭabā'ī has said that social justice denotes treating each member of society in accordance with their merit and ensuring everyone receives their rights. This social quality is an obligation that responsible individuals must observe [1]

The establishment of social justice is one of the most important teachings of divine prophets ('a). Hence they strived to explain its essence and scientific principles, inculcate its spirit within humanity, and compel its acceptance as a cornerstone upon which earthly life depends. Anyone with basic knowledge of religious teachings understands that the establishment of social justice enlivens God's religion. 

Thus, until justice prevails, true religion remains incomplete. Similarly, until universal social justice takes root, the fulfillment of religious and legal obligations remain unattained. [2]

The absence of social justice historically has been the cause of most revolutions. Noble-minded reformers have consistently started their movements with the of establishing social justice and eradicating discrimination. The Prophet (ṣ) said that “Justice in social struggle is like a guardian shield which protects people from oppression; and it is like a stable paradise that perpetually bestows its blessings” [3]

Although it is necessary for everyone to respect one another's rights, it is more important for a leader [to respect human rights]. In this regard, Imām 'Alī ('a) told his commanders that neglecting people's rights equates to ruin [4]. Additional, Imām Riḍā ('a) said that the Household (Ahl al-Bayt) of the Prophet (ṣ) are guardians and protectors of the believers' rights [5]

However, it is not solely leaders who must foster social justice; Islām has said both leaders and followers possess rights. Social justice can only thrive when everyone's rights are upheld. Imām 'Alī ('a) said that mutual respect between leaders and followers results in the elevation of righteousness, the revelation of religious principles, and the solidification of just characteristics.[6]

Characteristics of Social Justice

1.    Meritocracy

One of the most important characteristics of social justice is meritocracy, which means entailing the assignment of roles and responsibility based on individual merit. Justice mandates that the most qualified individuals are given precedence for opportunities and higher positions. 

Imām 'Alī ('a) instructed Mālik Ashtar to appoint individuals to different positions in accordance with their merit (Nahj al-Balāgha, letter to Malik Ashtar). The Prophet (s) emphasized that it is treachery to appoint less qualified people to positions of authority [7]

2.    Prioritizing the Rights of the Impoverished and Needy

Another characteristic of social justice is paying attention to the rights of the poor and needy. Injustice is a contributing factor to poverty, which in turn breeds various hardships. Luqman said that of all the bitterness he had encountered, poverty was the harshest. The Prophet (s) said that poverty, pain, enmity, and fire are never trivial [8], and that poverty represents a significant form of death [9]

These reports show that leaders have heavy responsibilities, because the poor need justice more than other people. 

3.    Respecting People's Rights 

When oppression becomes prevalent in society, leaders should not merely distance themselves from it; they ought to stand up and fight for the rights of the oppressed. In fact, all individuals must resist remaining silent when others endure oppression, as passivity equates to complicity in oppression.

Furthermore, not only oppression destroys everything, including culture, economics, wisdom, ability, talent, innovation, etc. but also it is the biggest obstacle to establish justice within society. Imam 'Alī ('a) asserted that ending oppression is a prerequisite for justice.

4.    Equity and Impartiality

It has been reported that one day a rich man and a poor man were sitting next to each other. The rich man pulled his face at the poor man and adjusting his clothes. Observing this the Prophet (ṣ) asked the rich man “Are you afraid that some of his poverty will be transmitted to you?” [10]

The Prophet (s), both in words and acts, paid attention to this important characteristic. For example, when a woman from the Banī Makhzūm tribe committed theft and the people asked the Prophet (s) to judge, her family, who were still influenced by the customs of the class system, considered execution of punishment to be shameful for their aristocratic family. As a result, they started looking for ways to prevent the punishment. To this end, they coerced Usama ibn Zayd, whom the Prophet (s) held in deep affection, to intercede with the Prophet (s) and halt the punishment. However, scarcely had Usama begun to speak when the Prophet (s) grew angry and said no one should stop him from implementing God's laws. Usama promptly sought forgiveness. Later that day, the Prophet (s), aiming to dispel any perception of favoritism, addressed the incident in a speech. He said “Throughout history, tribes and nations declined and vanished due to favoritism in justice’s administration. When both an aristocrat and a commoner committed the same crime, they would punish the commoner while granting impunity to the aristocrat. I swear by the God in whose hands hold my life that I shall spare no one from punishment, regardless of their social standing, whether high or low” [11]

On a different occasion, when Umm Hānī, Imām Alī's sister, went to see him, the Imam gave her twenty dirhams. When she asked her non-Arab bondswoman about her received amount, the female slave said she had also been given twenty dirhams. Incensed by this equality, Umm Hānī confronted her brother, Imam Ali, in protest. In response, the Imam sent her back with these words: “Go back, and may God forgive you. In the Book of God, we have not found any preference for Ishmael over Isaac” [12]

5.    Distinction between the Benevolent and the Malevolent

A leader must avoid treating benevolent and malevolent individuals equally, as this engenders injustice. Imām Alī ('a) instructed Mālik Ashtar to avoid treating benevolent and malevolent individuals equally, because doing so could discourage the benevolent and embolden the malevolent. Instead, everyone should be rewarded according to their deeds.[13]
   

       
          references 

1. (Al-Mīzān fī Tafsīr al-Qur'ān, vol. 24, pp. 243-246).
2. (Al-Ḥayāt, vol. 2, p. 97).
3. (al-Ḥadīth – Riwayāt-e Tarbiyyatī, vol. 2, p. 265). 
4. (Nahj al-Balāgha, letter no. 79)
5. (Musnad al-Imām al-Riḍā, ('a), vol. 1, p. 136). 
6. (Nahj al-Balāgha, sermon no. 216). 
7. (Al-Ta'ajub, p. 59).
8. (Nahj al-Faṣāha, saying no. 252)
9. (Nahj al-Balāgha, saying no. 163).
10. (Majmu'at Waram, vol. 1, p. 214).
11. (Ṣaḥīḥ Bukhārī, vol. 5, p. 152).
12. (Biḥār al-Anwār, vol. 40, p. 106).
13. (Nahj al-Balāgha, letter no. 53). 

Responsibility in Islam also covers every action that one is supposed to do as a Muslim and his/her interactions with others. Thus, human beings are responsible towards others including: whoever they interact with, whatever they have been given in this world, the divine duties they are expected to perform, and their surroundings and environment.

The responsibilities of a Muslim towards other human beings were discussed in the first part of the article. Here the focus is on the responsibilities towards some non-humans including divine duties [i] and, the property and belongings.

The Rights of Prayer as One's Responsibility in Islam

The right of the ritual prayer over one is to know that he\she is standing before God. Knowing that one should stand in His presence like a lowly servant who is inclined to approach his lord, and who is fearful and ashamed because of his\her sins, but still hopeful of His mercy [1], is our responsibility in Islam towards our prayers. 

He\she should also magnify Him through stillness, bowing of the head, humbleness of the limbs, yielding of the wing, and by saying the best supplications to Him. Then, one should beseech Him to save him\her from the punishments that he\she deserves for his\her faults and sins [1].

The Rights of Fasting

The right of fasting is to know it as a veil that God has set up over one’s tongue, hearing, and sight, private parts, and stomach, to protect him\her from the Fire. Whoever protects his\her parts of the body with the veil of fasting, can be hopeful to be saved from the punishments and the Fire.

But if one leaves his\her parts of the body to do freely unlawful (Haram) acts (e.g., looking at unlawful things and scenes that incite lust and encourage disobeying God) and does not fear God, he\she won’t be safe anymore [1]. 

The Rights of Pilgrimage

The right of pilgrimage is that one should know that he\she has immigrated from his\her sins to God and is standing in His presence. He\she should also know that it is through the pilgrimage that one’s repentance can be accepted and he\she performs an obligation made incumbent upon him\her by God [1].

The Rights of Charity

Of the rights of charity is to know that it is like storing away with God and is a deposit for which no witness is needed. Hence, it would be better to donate in private other than in public. Also, one should not remind others of what he\she has donated since the charity is like a saving whose benefit returns to the donor.

Otherwise, the same thing might happen to him\her when someone else does him\her a favor. Moreover, reminding others of the charity donated demonstrates the impure intention of the donor; like the tendency to show off or humiliate others [1].  

The rights of Sacrifice [ii]

Of the rights of the offering is to consider it as a way to expose oneself to God’s Mercy. So, one should make offering not for receiving others’ approval, but God’s approval.  Therefore, what others say about the offering should not matter [1].  

The Rights of Property

Of the rights of the belongings and property over one and one's responsibility in Islam towards them are to gain it through lawful (Halal) means, to spend it on lawful (Halal) purposes, and to utilize it such that it brings about blessing and salvation in this world and the Hereafter [1]. Imam Sadiq (AS) said that whoever makes money in unfair ways, he\she will lose it justly [2]. According to Surah Qasas, one should use the wealth that God has granted for doing good to others and preparing for the Hereafter (28:77). 

The property and wealth should be used to get God’s satisfaction. It is narrated from Prophet Muhammad (PBUH) that God will punish those who forget about the poor people among them and keep on raising money [3]. Hence, one should not prefer his\her belongings to his\her spirit such that he\she hesitate to use them for spiritual progression. Otherwise, others will inherit this property after his\her death. If they utilize the inherited property in unlawful (Haram) ways, he\she will also be punished for that. If the inheritors use the inherited property properly, they are the ones who will be rewarded [1].

Notes:
[i] The acts and practices that are obligatory (Wajib) or recommended (Mustahab) in Islam.
[ii] Animal sacrifice for the sake of God.

References:

1. Imam Zayn al-'Abidin (AS), “Treatise On Rights (Risalat al-Huquq)”.
2. S. al-Harrani “Tuhaf al-Uqul”, p. 321.
3. W. al.Hilli, “Tanbih al-khawatir wa nuzhat al-nawazir”, vol. 1, p. 10.