Beseech thou the One true God that He may enable everyone to repent and return unto Him. So long as one's nature yieldeth unto evil passions, crime and transgression will prevail.

Bahá’u’lláh, Tablets of Bahá’u’lláh, p. 70

In this Book He . . . prohibits . . . penance.

Bahá’u’lláh, The Kitab-i-Aqdas, p. 14

It is not Our purpose in addressing to thee these words to lighten the burden of Our woe, or to induce thee to intercede for Us with any one. No, by Him Who is the Lord of all worlds! We have set forth the whole matter before thee, that perchance thou might realize what thou hast done, might desist from inflicting on others the hurt thou hast inflicted on Us, and might be of them that have truly repented to God, Who created thee and created all things, and might act with discernment in the future. Better is this for thee than all thou dost possess, than thy ministry whose days are numbered.

Bahá’u’lláh, Gleanings from the Writings of Bahá’u’lláh, p. 229

Let repentance be between yourselves and God. He, verily, is the Pardoner, the Bounteous, the Gracious, the One Who absolveth the repentant.

Bahá’u’lláh, The Kitab-i-Aqdas, p. 30

My sole duty is to remind you of your failure in duty towards the Cause of God, if perchance ye may be of them that heed My warning. Wherefore, hearken ye unto My speech, and return ye to God and repent, that He, through His grace, may have mercy upon you, may wash away your sins, and forgive your trespasses. The greatness of His mercy surpasseth the fury of His wrath, and His grace encompasseth all who have been called into being and been clothed with the robe of life, be they of the past or of the future.

Bahá’u’lláh, Gleanings from the Writings of Bahá’u’lláh, p. 130

O God, my God! I beseech Thee by the sun of Thy grace, and the sea of Thy knowledge, and the heaven of Thy justice, to aid them that have denied Thee to confess, and such as have turned aside from Thee to return, and those who have calumniated Thee to be just and fair-minded. Assist them, O my Lord, to return unto Thee, and to repent before the door of Thy grace. Powerful art Thou to do what Thou willest, and in Thy grasp are the reins of all that is in the heavens and all that is on earth. Praise be unto God, the Lord of the worlds.

Bahá’u’lláh, Epistle to the Son of the Wolf, p. 106

O God, my God! I have turned in repentance unto Thee, and verily Thou art the Pardoner, the Compassionate.

Bahá’u’lláh, Bahá’í Prayers, p. 161

Thus have We recounted unto you the tales of the one true God, and sent down unto you the things He had preordained, that haply ye may ask forgiveness of Him, may return unto Him, may truly repent, may realize your misdeeds, may shake off your slumber, may be roused from your heedlessness, may atone for the things that have escaped you, and be of them that do good. Let him who will, acknowledge the truth of My words; and as to him that willeth not, let him turn aside.

Bahá’u’lláh, Gleanings from the Writings of Bahá’u’lláh, p. 130

We entreat God -- exalted and glorified be He -- to aid all men to be just and fair-minded, and to graciously assist them to repent and return unto Him. He, verily, heareth, and is ready to answer.

Bahá’u’lláh, Epistle to the Son of the Wolf, p. 33

But this wronged one, this prisoner, did his utmost to hide and veil their doings, that haply they might regret and repent.

‘Abdu’l-Bahá, The Will and Testament, p. 24

Repentance is the return from disobedience to obedience. Man, after remoteness and deprivation from God, repents and undergoes purification: and this is a symbol signifying "O God! make my heart good and pure, freed and sanctified from all save Thy love.

‘Abdu’l-Bahá, Some Answered Questions, p. 91

The principle of baptism is purification by repentance. John admonished and exhorted the people, and caused them to repent; then he baptized them. Therefore, it is apparent that this baptism is a symbol of repentance from all sin: its meaning is expressed in these words: "O God! as my body has become purified and cleansed from physical impurities, in the same way purify and sanctify my spirit from the impurities of the world of nature, which are not worthy of the Threshold of Thy Unity!"

‘Abdu’l-Bahá, Some Answered Questions, p. 91

Verily Thou art the Ever-Forgiving, He to Whom repentance is due, He Who forgiveth even the most grievous of sins.

‘Abdu’l-Bahá, Selections from the Writings of ‘Abdu’l-Bahá, p. 233

Restoration of voting rights often requires repentance by the offender, but the standards governing such repentance must not be confused with those relative to the repentance of a Covenant-breaker. Expression of repentance is the way in which a former Covenant-breaker makes known his change of heart and involves the fact that the individual knows what it is that he has done wrong and says so. In the case of deprivation of voting rights, however, the repentance required to be shown differs in degree and form from case to case. At one extreme is the case of a believer who is no longer able to rectify the wrong he has committed -- for example when he has lost his voting rights for marrying without parental consent and the parents have since died -- in such a case the factor of repentance is particularly important. At the other extreme is the case of a believer who has been deprived of his voting rights because the Assembly is convinced by the evidence that he was guilty of the offense, but who maintains that, in spite of all appearances to the contrary, he is innocent. There is no requirement that such a believer admit guilt before the voting rights can be restored. The believer must, however, comply with the Assembly's instructions as to his behavior. In between these extremes are many cases where the very rectifying of the error can be held to constitute repentance.

Universal House of Justice, NSA USA - Developing Distinctive Bahá’í Communities

Haji Muhammad-Baqir was a well-known merchant, foremost among the believers in faith, certitude and enthusiasm, and was serving the Cause with devotion and self-sacrifice. This man attained the presence of Bahá’u’lláh in Baghdad. There He wrote a letter to Him and begged for wealth and prosperity. In answer, this exalted and wonderful Tablet was revealed for him. In it Bahá’u’lláh stated that his request would be granted and that the doors of prosperity and wealth would be opened for him from every direction. He warned him, however, to be on his guard and not to allow riches to become a barrier and make him heedless. Now you are here to attain the presence of Bahá’u’lláh and in the future you will witness that this man will be overtaken with fear to such an extent that he will renounce God and His Cause. Not long after, he will make substantial losses, following which he will write a letter to Bahá’u’lláh and repent. God will then turn his losses into profit and he will become again highly successful in his business and will emerge as the foremost merchant in Constantinople  and Tabriz. However, this time he will wax prouder than before, more heedless and deprived... This time he will lose all his possessions, will be unable to continue trading and will become helpless in arranging his affairs. It is then that he will repent and return, and will be content to live as a poor man. He will spend the days of his life in the service of the Cause of God. His end will be blessed and he will receive great confirmations from God.' He then said to me: 'Remember all these things, for they will come to pass, and you shall witness them.'

Adib Taherzadeh, Revelation of Bahá’u’lláh, v2, p. 277-278

In spite of the harrowing afflictions that the Blessed Beauty suffered at the hand of this half-brother, He, in the Kitáb-i-Aqdas, reminds Mirza Yahya of the early days of his life when He, as a token of His bounty, nurtured him so that he might become a worthy instrument for the service of the Cause. He asks him to call to mind the times when he used to be summoned to stand before Bahá’u’lláh and take down the verses of God which were revealed by Him, counsels him to return to God after his shameful rebellion against His Manifestation, and assures him that God would forgive all his iniquities should he now repent and beg forgiveness from Him.

Adib Taherzadeh, The Revelation of Bahá’u’lláh v 3, p. 373-374

In the meantime some of the Covenant-breakers in 'Akká repented and returned to the community, others were disillusioned and became helpless and began to wander around.

Adib Taherzadeh, The Child of the Covenant, p. 195

It did not take very long before a number of those who had been misled by him [Mason Remy] realized their mistake, repented and returned to the community or withdrew from the Faith altogether.

Adib Taherzadeh, The Child of the Covenant, p. 370

Men may be made in the image of God, yet (as the Bible presents it) the history of the tribes and peoples and nations of the world, of the Hebrews and the Gentiles, reflects at no time the order and harmony and the happiness of a divine world. It is a tale of turmoil and vicissitude, of struggle and trouble, of sorrow and loneliness and penitence, of bitter shame, and hopes lost and hearts broken.

George Townshend, The Heart of the Gospel, p. 20