The Duties of the Heart, by Rabbi Bachye, tr. by Edwin Collins, , at sacred-texts.com
The intention of all separation from the world is only so that one may concentrate the whole heart upon the one object of love for the Creator, and that one may be filled with longing to fulfil His will. This perfect love of God is the primary aim and intention, as well as the end and fulfilment, of all obligations taught by Reason, by Scripture, or by Tradition.
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This love of God is the yearning of the soul for the Creator, and her turning, of her own accord,
towards Him, so that she may be united with His light, which is the highest. That is, that the soul, which is herself pure spirit, inclines, more than any other spiritual being, to her like, and in her very nature recedes from that which is her opposite:—from gross matter.
They who love God will do all that is right, without the hope of reward, and will forsake all that is evil, without the fear of punishment. They will also have no fear of anything, or of any person, in this or any other world, except of the Creator alone. And they will be indifferent to the praise and blame of men in doing the will of God. They will be pure in body as well as in mind, and fly from evil deeds of all kinds. They will serve the Creator not only in obedience to the laws of revelation, some of which are only binding in given circumstances, but also in the duties that are commanded by Reason and Conscience, and with every good spiritual quality.