“Many are called, but few are chosen.”

"Know that the order and the perfection of the whole universe require that existence should appear in numberless forms. For existing beings could not be embodied in only one degree, one station, one kind, one species and one class; undoubtedly, the difference of degrees and distinction of forms, and the variety of genus and species, are necessary—that is to say, the degree of mineral, vegetable, animal substances, and of man, are inevitable; for the world could not be arranged, adorned, organized and perfected with man alone. In the same way, with only animals, only plants or only minerals, this world could not show forth beautiful scenery, exact organization and exquisite adornment. Without doubt it is because of the varieties of degrees, stations, species and classes that existence becomes resplendent with utmost perfection."
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"It is from the bounty of God that man is selected for the highest degree; and the differences which exist between men in regard to spiritual progress and heavenly perfections are also due to the choice of the Compassionate One. For faith, which is life eternal, is the sign of bounty, and not the result of justice. The flame of the fire of love, in this world of earth and water, comes through the power of attraction and not by effort and striving. Nevertheless, by effort and perseverance, knowledge, science and other perfections can be acquired; but only the light of the Divine Beauty can transport and move the spirits through the force of attraction. Therefore, it is said: “Many are called, but few are chosen.” (Matt. 22:14)

-`Abdu'l-Bahá, Some Answered Questions, pp. 129-130