One who is able to help an oppressed person or to condemn an evil

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said: "Your Lord says: By My Might and My Majesty, I will surely take revenge on the oppressor, whether soon or late, and I will surely take revenge on the one who sees an oppressed person and has the ability to help him, yet does not do so."
Al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat, and its chain contains a narrator whom I do not know.

Sayyiduna Sahl bin Hunayf (may Allah be pleased with him) reports that the Prophet (peace and blessings be upon him) said: "Whoever has a believer humiliated in his presence and does not help him, though he has the ability to help him, Allah Almighty will humiliate him before all creation on the Day of Resurrection."
Ahmad and al-Tabarani recorded it; its chain contains Ibn Lahi'ah, who is hasan al-hadith (fair in hadith), though there is weakness in him; the rest of its narrators are thiqat (trustworthy).

Adi bin Adi al-Kindi has transmitted this statement of Mujahid: My master narrated this hadith to me, that he heard his grandfather say: I heard the Prophet (peace and blessings be upon him) say: "Indeed, Allah Almighty does not punish the common people for the deeds of the elite until the situation is that they (that is, the common people) see evil among them and have the ability to denounce it, yet do not denounce it. When they do that, Allah Almighty punishes the elite and the common people (all of them)."
Ahmad recorded it through two routes, one of which is this, and the other is from Adi bin Adi, who said: My master narrated this hadith to me, and that is the correct one. Al-Tabarani recorded it in the same way. Its chain contains a narrator who is not named, and the narrators of one of its two chains are thiqat (trustworthy).

Sayyiduna Jabir (may Allah be pleased with him) and Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him) narrate that the Prophet (peace and blessings be upon him) said: "Whoever forsakes a Muslim in a place where his honour is being diminished and his sanctity violated, Allah Almighty will forsake that person in a place where he will be wanting Allah Almighty's help. And whoever helps a Muslim in a place where his honour is being diminished or his sanctity violated, Allah Almighty will help him in a place where he will be wanting Allah Almighty's help." (Allamah al-Haythami says:) I say: Abu Dawud has recorded only the narration of Sayyiduna Jabir (may Allah be pleased with him).
Al-Tabarani recorded it in al-Mu'jam al-Awsat, and its chain is hasan (good).

Sayyiduna Imran bin Husayn (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever helps his brother in his absence, while he has the ability to help him, Allah Almighty helps that person in this world and the Hereafter."
Al-Bazzar recorded it; it is transmitted through several chains, one of which is mawquf on Sayyiduna Imran (may Allah be pleased with him), and the narrators of one of the several chains of the marfu' version are the narrators of the Sahih. Al-Tabarani also recorded it.

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: I heard the Prophet (peace and blessings be upon him) say: "A man was laid in his grave, and two angels came to him. They said to him: We are going to strike you a blow. The man asked them: Why will you strike me? They struck him a blow because of which his grave was filled with fire. Then they left him until, when he came to and his terror had gone, he said to them: Why did you strike me? The two angels said: You used to pray while you were without ablution (or not fully purified), and you passed by an oppressed man and did not help him."
Al-Tabarani recorded it; its chain contains Yahya bin Abdullah al-Babulti, who is da'if (weak).