What did the classical scholars say about sadness and depression?

"separation from loved ones, the wise in his decrees. He turned away from his sons and said, O my sorrow for Joseph, as his new grief reminded him of the old sorrow. As some have said, move your heart wherever you wish among passions. Love is only for the first beloved. And another said, he reproached me at the graves for weeping, my friend for the tears overflowing. He said, will you weep for every grave you see, the grave that lies between the dunes and the plains? I said to him, indeed, sorrow begets sorrow. So leave me, for this is all the grave of Malik. His eyes turned white from grief, meaning from excessive weeping. He was"

"to him, indeed, sorrow begets sorrow. So leave me, for this is all the grave of Malik. His eyes turned white from grief, meaning from excessive weeping. He was suppressing his sorrow due to the intensity of his grief and longing for Joseph. When his sons saw his longing and pain, they said to him out of compassion, By Allah, you will not cease remembering Joseph until you are on the verge of ruin or become among the perished. They suggested he be gentle with himself for the best. He said, I only complain of my distress and sorrow to Allah, and I know from Allah what you do not know. He told his sons that he did not complain to"

"truthful. He replied, rather, your souls have enticed you to something, so patience is most fitting, perhaps Allah will bring them to me altogether, indeed he is the knowing, the wise. Turning away from them, he lamented, O my sorrow over Joseph, and his eyes became white from grief as he suppressed his sorrow. They said, by Allah you will not cease remembering Joseph until you become fatally ill or perish. He responded, I only complain of my suffering and my grief to Allah, and I know from Allah what you do not know. O my sons, go and find out about Joseph and his brother, and do not despair of relief from Allah."

"In such a case, there is no reason to grieve for the absence of grief. The author of "المَنَازِل" states that the elite are not in the station of grief, for grief is a loss, and the elite are people of experience. If he means they should not deliberately seek grief, he is correct. But if he means that grief does not occur to them, that is not the case, as grief is a natural necessity, though it is not a station."

"Its absence is a deficiency, so one grieves for the loss of grief, just as one weeps for the loss of weeping and fears the absence of fear. This is debatable, as grief for the loss of grief is only commendable when one is preoccupied with praiseworthy joy, which is the joy in اللّٰه's grace and mercy. In such a case, there is no reason to grieve for the absence of grief."

"In this context, there are three degrees. The first degree is the happiness of taste. It dispels three sorrows: a sorrow born from the fear of separation, a sorrow attacked by the darkness of ignorance, and a sorrow stirred by the loneliness of separation. Happiness is the opposite of sorrow, and sorrow does not coexist with it, as it dispels it."

"It can also mean anger, as in the verse: "But when they angered Us, We took retribution from them" from سُورَة الزُّخْرُف. In this context, it refers to the sorrow over what is hidden from him of his desires or his true state. When it is said, "And if he speaks, he speaks with sorrow," it means that if this person expresses anything that indicates sorrow over what is hidden from him, the source of his expression and speech is his sorrow over what is concealed from him."

"Joy is a pleasure that fills the heart upon perceiving the beloved and attaining the desired. From this perception, joy and happiness arise. Similarly, sorrow and grief come from the loss of the beloved, creating a state of sorrow and grief. اللّٰه mentions the command to rejoice in His bounty and mercy following His words: "O mankind, there has come to you instruction from your Lord and healing for what is in the breasts and guidance and mercy for the believers.""

"do not rush to prostrate until you weep; if none of you can weep, then let his heart weep." To encourage oneself to weep, one should bring sadness to the heart, as weeping arises from sadness. The Prophet, peace be upon him, said, "The Qur’an was revealed with sorrow, so when you recite it, be sorrowful. To cultivate this sadness, reflect on the warnings, threats, covenants, and oaths in the Quran, and consider your own shortcomings in fulfilling its commands and prohibitions."

"To cultivate this sadness, reflect on the warnings, threats, covenants, and oaths in the Quran, and consider your own shortcomings in fulfilling its commands and prohibitions. This reflection leads to inevitable sorrow and weeping. If one is not moved to sorrow and weeping as the pure-hearted are, let him weep for the lack of sorrow and weeping, for that is the greatest of misfortunes."