‎"Naturally there will be periods of distress and difficulty, and even severe tests; but if the person turns firmly towards the Divine Manifestation, studies carefully His spiritual teachings and receives the blessings of the Holy Spirit, he will find that in reality these tests and difficulties have been the gifts of God to enable him to grow and develop. Thus you might look upon your own difficulties in the path of service. They are the means of your spirit growing and developing. You will suddenly find that you have conquered many of the problems which upset you, and then you will wonder why they should have troubled you at all." - Shoghi Effendi, Living the Life, pp. 35-36.

"I beg Thee to forgive me, O my Lord, for every mention but the mention of Thee, and for every praise but the praise of Thee, and for every delight but delight in Thy nearness, and for every pleasure but the pleasure of communion with Thee, and for every joy but the joy of Thy love and of Thy good-pleasure, and for all things pertaining unto me which bear no relationship unto Thee, O Thou Who art the Lord of lords, He Who provideth the means and unlocketh the doors." - The Báb

‎"... Life in this world is a succession of tests and achievements, of falling short and of making new spiritual advances. Sometimes the course may seem very hard, but one can witness, again and again, that the soul who steadfastly obeys the law of Baha'u'llah, however hard it may seem, grows spiritually, while the one who compromises with the law for the sake of his own apparent happiness is seen to have been following a chimera: he does not attain the happiness he sought, he retards his spiritual advance and often brings new problems upon himself." -- From a letter dated 6 February 1973 written by the Universal House of Justice to all National Spiritual Assemblies, published in "Messages from the Universal House of Justice 1968-1973, p. 106

‎"I say unto you that any one who will rise up in the Cause of God at this time shall be filled with the spirit of God, and that He will send His hosts from heaven to help you, and that nothing shall be impossible to you if you have faith. And now I give you a commandment which shall be for a Covenant between you and me: that ye have faith; that you faith be steadfast as a rock that no storms can move, that nothing can disturb, and that it endure through all things even to the end; even should ye hear that your Lord has been crucified, be not shaken in your faith; for I am with you always, whether living or dead; I am with you to the end. As ye have faith so shall your powers and blessings be. This is the standard—this is the standard—this is the standard." - ‘Abdu’l-Bahá, Bahá’í Scriptures, p. 503-504

‎"O ye that stand fast in the Covenant! When the hour cometh that this wronged and broken winged bird will have taken its flight unto the Celestial Concourse, when it will have hastened to the Realm of the Unseen, and its mortal frame will have either been lost or hidden neath the dust, it is incumbent upon the Afnan that are steadfast in the Covenant of God and have branched from the Tree of Holiness, the Hands of the Cause of God (the glory of the Lord rest upon them), and all the friends and loved ones, one and all, to bestir themselves and arise with heart and soul and in one accord to diffuse the sweet savors of God, to teach His Cause and to promote His Faith. It behooveth them not to rest for a moment, neither to seek repose. They must disperse themselves in every land, pass by every clime, and travel throughout all regions. Bestirred, without rest, and steadfast to the end, they must raise in every land the triumphal cry of Ya-Baha'u'l-Abha, must achieve renown in the world wherever they go, must burn brightly even as a candle in every meeting, and must kindle the flame of Divine Love in every assembly; that the Light of Truth may rise resplendent in the midmost heart of the world, that throughout the East and throughout the West a vast concourse may gather under the shadow of the Word of God, that the sweet savors of Holiness may be diffused, that faces may shine radiantly, hearts be filled with the Divine Spirit and souls be made heavenly. In these days the most important of all things is the guidance of the nations and the peoples of the world. Teaching the Cause is of utmost importance, for it is the head corner-stone of the foundation itself. This wronged servant has spent his days and nights in promoting the Cause, and urging the peoples to service. He rested not a moment, till the fame of the Cause of God was noised abroad in the world, and the Celestial Strains from the Abha Kingdom roused the East and the West. The beloved of God must also follow the same example. This is the secret of faithfulness, this is the requirement of servitude to the Threshold of Baha."
We need but glance at the Words of Baha'u'llah and the Epistles of Abdu'l-Baha to realize the great privilege of teaching the Cause, its vital necessity, its supreme urgency, and its wide-reaching effects. These are the very words of Abdu'l-Baha: -
"In these days, the Holy Ones of the Realm of Glory, dwelling in the all-highest Paradise, yearn to return unto this world, and be of some service to the Cause of Baha'u'llah and prove their servitude to the Threshold of Abha beauty."
What a wondrous vision these words unfold to our eyes! How great our privilege to labor in this Day in the Divine Vineyard! Is it not incumbent upon us to arise and teach His Cause with such an ardor which no worldly adversity can quell, nor any measure of success can satiate?
(Shoghi Effendi: Baha'i Administration, Pages: 36-37)

Although you seem to feel that your prayers have not so far been answered, and do no longer have any hope that your material conditions will ameliorate, the Guardian wishes you nevertheless not to allow such disappointments to undermine your faith in the power of prayer, but rather to continue entreating the Almighty to enable you to discover the great wisdom which may be hidden behind all these sufferings. For are not our sufferings often blessings in disguise, through which God wishes to test the sincerity and depth of our faith, and thereby make us firmer in His Cause?

...The true worshipper, while praying, should endeavour not so much to ask God to fulfil his wishes and desires, but rather to adjust these and make them conform to the Divine Will. Only through such an attitude can one derive that feeling of inner peace and contentment which the power of prayer alone can confer.

(From a letter dated 26 October 1938 to an individual believer; cited in The Compilation of Compilations vol II, pp. 239-240, #1768).

Abdu'l-Baha', was sad on one occasion because he had learned of an incident of backbiting among the friends and said:

"I don't know where the people have learned the art of backbiting?" 

A Baha'i believer answered, 'Beloved Master, from God himself.' 
The Master said, "How?"

The Baha'i answered, 'Adam ate one apple only in his whole life and God mentioned it to everyone in the Old Testament, in the New Testament, and in the Qur'an........'

(From A Seminar conducted by the Hand of the Cause of God A. Q. Faizí in Hawaii in 1967).