A. Hatred (al-Bughd) is the inclination of the soul to flee away from things it finds repulsive.
Raghib al-Asfahani, al-Mufradat

Unsanctioned hatred occurs when the repulsiveness the soul finds is unjustified and leads to forbidden actions against the object of ones hatred.

A.1. Negative Consequences of Unsanctioned Hatred

1. Hatred of others incurs the wrath and hatred of Allah. Kama tadeenu tudaan (As you behave you will be treated)
2. Hatred blinds the heart and extinguishes the light resulting from sincere worship.
3. One who hates people cannot bear to live among them and he will turn in on himself and live in isolation or in an alienated state.
4. Such a person will become a cause for tearing apart the social fabric.
5. Hatred is an indication of a vile and base soul.
Mentioned in Nadra al-Na’im

A.2. Texts from the Qur’an and the Sunnah Concerning Hatred

O Believers! Take not as your intimate advisors those outside of your ranks who will spare nothing to bring about your ruin. They desire that you fall into grave hardship. Hatred has issued from their mouths, and what they conceal is even worse. We have made the signs clear to you if you would only reflect.
Qur’an 3:118

Rather, Satan desires to place enmity and hatred between you with wine and gambling, and to turn you away from the remembrance of Allah and away from Prayer. Will you not then cease?
Qur’an 5:91

You have an excellent example in Abraham and those with him, when they said to their people, “We are free of you and of what you worship other than Allah. We have rejected you and there has appeared between us and you enmity and hatred forever, unless you return to the path of Allah…
Qur’an 60:4

The Prophet, peace upon him, mentioned, “Do not hate one another. Do not envy one another. Do not turn your backs to each other. Be servants of Allah, brothers. It is not permissible for a Muslim to boycott his for more than three days.”
Bukhari, #6065

The Prophet, peace upon him said, “A sign of the hypocrite is hatred of the Ansar, and a sign of the believer is love of the Ansar.”
Muslim, #74

The Prophet, peace upon him, said, “The disease of the nations will creep up on you –jealousy and hatred. It is a razor. I am not saying that it cuts hair, rather it cuts down religion. I swear by the one who holds my life in His hand, you will not enter Paradise until you believe. You will not believe until you love one another. Shall I not alert you to something that will affirm this for you? Spread the peace among yourselves.”
Tirmidhi, #2510

The Prophet, peace upon him warned, “My community will be afflicted by the disease of the nations.” They asked, “O Messenger of Allah! What is the disease of the nations?” He said, “Excessive merriment, rampant consumerism, conspiring against one another, hatred, and jealousy until there is open sedition.”
Hakim, 4:168

A.3. Sayings of the Scholars Concerning Hatred

Don’t be totally obsessed with your beloved for one day you may have to hate him/her; and don’t be totally repulsed by the object of your hatred for one day you may have to love him/her.
Abu Hurayra, Tirmidhi, #1996

Don’t convey falsehood to knowledgeable people lest they hate you. Don’t share wisdom with fools lest they belie you. Don’t withhold knowledge from students lest they view you as a sinner, and don’t place knowledge with other than its rightful possessors lest they declare you an ignoramus. There is a right over your knowledge just as there is a right over your wealth.
Kathir bin Murra, Sunan al-Darimi 1:88

Constant condemnation generates hatred.
Arab Parable, al-Mustadraf