Remembrance of God is like the rain and dew which bestow freshness and grace on
flowers and hyacinths, revive them and cause them to acquire fragrance, redolence and renewed charm. “And thou hast seen the earth dried up and barren: but when We send down the rain upon it, it stirreth and swelleth, and groweth every kind of luxuriant herb.”
 Strive thou, then, to praise and glorify God by night and by day, that thou mayest attain infinite freshness and beauty.
(‘Abdu’l-Bahá, from a Tablet—translated from the Persian)

Strain every nerve to acquire both inner and outer perfections, for the fruit of the human tree hath ever been and will ever be perfections both within and without. It is not desirable that a man be left without knowledge or skills, for he is then but a barren tree. Then, so much as capacity and capability allow, ye needs must deck the tree of being with fruits such as knowledge, wisdom, spiritual perception and eloquent speech.   Baha’I writings
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From the Writings of Bahá’u’lláh