Among them is the tradition, "And when the Standard of Truth is made manifest, the people of both the East and the West curse it." . . . It is evident that the reason for such behaviour is none other than the annulment of those rules, customs, habits, and ceremonials to which they have been subjected.

Bahá’u’lláh, The Kitab-i-Iqan, p. 237

Defile not your tongues with the cursing and reviling of any soul.

Bahá’u’lláh, Tablets of Bahá’u’lláh, p. 27

Did they whom you curse, upon whom ye invoke evil, act differently from yourselves?

Bahá’u’lláh, Gleanings from the Writings of Bahá’u’lláh, p. 222

O thou who hast gone astray! Thou hast neither seen Me, nor associated with Me, nor been My companion for the fraction of a moment. How is it, then, that thou hast bidden men to curse Me? Didst thou, in this, follow the promptings of thine own desires, or didst thou obey thy Lord?

Bahá’u’lláh, Tablets of Bahá’u’lláh, p. 207

It is not becoming in man to curse another; it is not befitting that man should attribute darkness to another; it is not meet that one human being should consider another human being as bad; nay, rather, all mankind are the servants of one God; God is the Father of all; there is not a single exception to that law.

‘Abdu’l-Bahá, The Promulgation of Universal Peace, p. 266

Let us realize and resolve that though we are beaten, banished, cursed, spat upon and led forth to be killed . . . .

‘Abdu’l-Bahá, The Promulgation of Universal Peace, p. 73

The Jews in turn regarded the Christians as infidels and the Muslims as enemies and destroyers of the law of Moses. Therefore, they call down vengeance upon them and curse them even to this day.

‘Abdu’l-Bahá, The Promulgation of Universal Peace, p. 266

An angry multitude was tormenting him with their threats, their blows and curses.

Shoghi Effendi, The Dawn-Breakers, p. 276

Cursing and execration were indulged in to a fearful extent. It was dangerous for a Jew or a Zoroastrian to walk in the street on a rainy day, for if his wet garment should touch a Muhammadan, the Muslim was defiled, and the other might have to atone for the offense with his life. If a Muhammadan took money from a Jew, Zoroastrian or Christian he had to wash it before he could put it in his pocket. If a Jew found his child giving a glass of water to a poor Muhammadan beggar he would dash the glass from the child's hand, for curses rather than kindness should be the portion of infidels!

Dr. J.E. Esslemont, Bahá’u’lláh and the New Era, p. 11

Cursing is a common practice among the Persians, especially among the clergy who pride themselves in pronouncing a person to be Mal'un (accursed) with a guttural sound of the letter 'U'. By doing so, not only has the clergy put a curse on someone, but by pronouncing the letter 'U' with a guttural sound he proudly puts himself in the category of a scholar of the Arabic language. Thus he makes a great impression upon the untutored multitude who never know how to use a guttural sound and are lost in admiration for one who does.

Adib Taherzadeh, The Revelation of Bahá’u’lláh v 4, p. 341

In the above passage Bahá’u’lláh speaks of cursing by the people. It was a common practice by the enemies of the Faith to curse its Founders. When a Bahá’í was condemned to die for his faith, he would invariably be given a chance to recant. If he did, his life would be saved. But often the mere act of recanting was not considered sufficient. The basic reason for this was that dissimulation of one's faith was considered by the followers of Shí'ah Islam to be a legitimate action to take at times of danger. The practice of dissimulation was widespread among the population of Persia for centuries. Although it amounted to telling a lie concerning one's beliefs, no blame was attached to it. It was considered to be an acceptable way of life, and even some believers in the early days of the Faith followed this practice in order to save their lives. This is why at times some of the enemies of the Faith insisted that it was not sufficient for a Bahá’í to recant his faith. In addition to recanting he had to curse Bahá’u’lláh, the Founder of the Faith, in order that his life might be saved.  Cursing was considered to be a test of sincerity for the one who was asked to recant. It must be noted that it is forbidden for a Bahá’í to dissimulate his faith.

The practice of cursing was not limited to these occasions only; it was much more widespread. Cursing Bahá’u’lláh and other Central Figures of the Faith was considered by the Muslim clergy in Persia to be an act of devotion to God and a great service to Islam. They often cursed the Faith from the pulpit during their sermons. Many a devout Muslim of the Shí'ah sect would take pride in hurling imprecations at the Founders of the Faith in public when a Bahá’í passed him by. This was one form of severe mental persecution which many Bahá’ís had to endure day after day.

Adib Taherzadeh, The Revelation of Bahá’u’lláh v 4, p. 92

One of his worst habits was to insult people and curse them in the most bitter and vile language.

Abu'l-Qasim Faizi, A Flame of Fire

Speaking against God means to keep far from Him -- to deny Him -- this is the same as cursing Him.

Compilations, Bahá’í Prayers 9, p. 50

The Christians and Muhammadans considered the Jews as satanic and the enemies of God. Therefore they cursed and persecuted them. Great numbers of Jews were killed, their houses burnt and pillaged, their children carried into captivity. The Jews in turn regarded the Christians as infidels, and the Muhammadans as enemies and destroyers of the laws of Moses; therefore they called down vengeance upon them and curse them even to this day.

Dr. J.E. Esslemont, Bahá’u’lláh and the New Era, p. 159

The One God testifies that were ye to reflect a little, ye would find that aside from all these established facts and mentioned proofs, the very cursing, execration and rejection by the people of the earth are the greatest proof and weightiest evidence of the truth of these heroes of the field of severance and resignation.

Compilations, Bahá’í Scriptures, p. 61