Behinat Olam, from which Shirei ha-Behinah is derived, is a poetical and philosophical work on the vanity of worldly things by R. Jedaiah ben Abraham Bedersi (ha-Penini, c. 1270-1340). Behinat Olam, the most famous of Jedaiah’s works, is also known as Shamayim la-Rom from its initial words, "The sky for height and the earth for depth" (Proverbs 25:3). Behinat Olam discusses the uncertainties of fortune and the correct path to be followed. Utilizing rich imagery, Behinat Olam is a mixture of philosophy and enthusiastic religion, combined with doleful asceticism. It begins with a description of the character of man, particularly those who are wise, noting their capabilities and many accomplishments. Nevertheless, the sage is not exempt from the vicissitudes of life, Afor the sword of death stabs both the philosopher and the boor, and death makes man equivalent to the animals. Man's superiority is his immortality, to be strived for throughout his life. All else is vain and futile, this world a dark cave, a dumping place for refuse. The vanity of temporal pleasures and possessions are described; this world is a tempestuous sea, and time but a bridge over the abyss connecting that which preceded existence with eternity. There is a discussion of the soul, its heavenly origin, tribulations and struggles in its earthly sojourn in the body. The soul accompanies man beyond the grave, but man, enraptured with the insidious charms of this world does not attempt to improve the best part of himself, his years roll away in pursuit of illusions.

The last part of Behinat Olam is devoted to pointing out what constitutes the correct path, the manner in which one should live, and that happiness can only be found in observance of the Law. The Torah is a flame originating in a heavenly spark, whereas man is the torch enkindled by the flame; the body being the wick, the soul the pure oil. Jedaiah does not advocate study alone, however, for man must live a full life, participating in the enjoyments of life, but in moderation.