Why do people oppress one another, and will they pay the price for their injustice, and is the supplication of the oppressed answered?

We advise the questioner to consistently recite the prescribed morning and evening supplications for protection. Injustice is a grave sin, and Allah has forbidden it in the Hadith Qudsi: "O My servants, I have forbidden injustice for Myself and made it forbidden amongst you, so do not commit injustice against one another." Allah has promised severe punishment for the oppressors. The cause of injustice is weakness of faith and intellect, and a lack of fear. The oppressor will pay the price for their injustice if they die before repenting and seeking absolution from the wronged party. Allah may also punish them in this world. The supplication of the oppressed is answered, as stated in the Hadith: "Beware of the supplication of the oppressed, for there is no barrier between it and Allah."