Moses de Leon, The Book of the Pomegranate, p. 225
Jewish Mysticism
For a man who loves his creator, when he arrives as the recitation of the shema, in the verse, “and you shall love,” he should intend his mind and thoughts to the love of his creator as though he is giving his soul to Him in love and with a perfect heart, and he should receive death upon himself. It is an obligation for every man to resolve upon this every day.
Translated by Hartley Lachter