Bahá’u’lláh warns Queen Victoria how God shall “bring to naught” the work of any one who “turneth aside” from His Message and, and “swelleth with pride”

As to him who turneth aside, and swelleth with pride, after that the clear tokens have come unto him, from the Revealer of signs, his work shall God bring to naught. He, in truth, hath power over all things. Man’s actions are acceptable after his having recognized [the Manifestation]. He that turneth aside from the True One is indeed the most veiled amongst His creatures. Thus hath it been decreed by Him Who is the Almighty, the Most Powerful. 

- Bahá’u’lláh  (Quoted by Shoghi Effendi, ‘The Promised Day Is Come’)

Bahá’u’lláh praises Queen Victoria for forbidding “the trading in slaves”

We have been informed that thou hast forbidden the trading in slaves, both men and women. This, verily, is what God hath enjoined in this wondrous Revelation. God hath, truly, destined a reward for thee, because of this. He, verily, will pay the doer of good his due recompense, wert thou to follow what hath been sent unto thee by Him Who is the All-Knowing, the All-Informed. 

- Bahá’u’lláh  (Quoted by Shoghi Effendi, ‘The Promised Day Is Come’)

Bahá’u’lláh counsels Queen Victoria

Lay aside thy desire, and set then thine heart towards thy Lord, the Ancient of Days. We make mention of thee for the sake of God, and desire that thy name may be exalted through thy remembrance of God, the Creator of earth and heaven. He, verily, is witness unto that which I say. 

- Bahá’u’lláh  (Quoted by Shoghi Effendi, ‘The Promised Day Is Come’)

Bahá’u’lláh proclaims His station to Queen Victoria

To Queen Victoria Bahá’u’lláh has written: “O Queen in London! Incline thine ear unto the voice of thy Lord, the Lord of all mankind, calling from the Divine Lote-Tree: Verily, no God is there but Me, the Almighty, the All-Wise! Cast away all that is on earth, and attire the head of thy kingdom with the crown of the remembrance of thy Lord, the All-Glorious. He, in truth, hath come unto the world in His most great glory, and all that hath been mentioned in the Gospel hath been fulfilled. The land of Syria hath been honored by the footsteps of its Lord, the Lord of all men, and north and south are both inebriated with the wine of His presence. Blessed is the man that inhaled the fragrance of the Most Merciful, and turned unto the Dawning-Place of His Beauty, in this resplendent Dawn. The Mosque of Aqsá vibrateth through the breezes of its Lord, the All-Glorious, whilst Bathá [Mecca] trembleth at the voice of God, the Exalted, the Most High. Whereupon every single stone of them celebrateth the praise of the Lord, through this Great Name. 

- Shoghi Effendi  (‘The Promised Day Is Come’)

Bahá’u’llah lets Czar Alexander II know the blessedness of a king who has acknowledged His Cause

...Blessed be the king whose sovereignty hath withheld him not from his Sovereign, and who hath turned unto God with his heart. He, verily, is accounted of those that have attained unto that which God, the Mighty, the All-Wise, hath willed. Erelong will such a one find himself numbered with the monarchs of the realms of the Kingdom. Thy Lord is, in truth, potent over all things. He giveth what He willeth to whomsoever He willeth, and withholdeth what He pleaseth from whomsoever He willeth. He, verily, is the All-Powerful, the Almighty. 

- Bahá’u’llah  (Quoted by Shoghi Effendi in ‘The Promised Day Is Come’)