Tu Bishvat is sometimes referred to as the day in which the sap begins to rise in the trees. From where does this teaching arise? “A Tree Comes of Age” by Rabbi Dr. Sperber was originally given as a lecture on Parashat Yitro 5769/ February 14, 2009 and published on Bar-Ilan University’s Parashat Hashavua Study Center’s website, here. We have formatted the essay adding a number of the sourcetexts referred to in the lecture and all referenced citations. . . .

The Shimmush Tehillim is a medieval work providing prescriptive theurgical associations for Psalms and verses from Psalms. It has been historically attributed to Rav Hai Gaon (939-1038 CE) but any definitive statement of authorship is lacking. The suggestion that portions of the Shimush Tehillim were authored during the late Geonic period in Iraq isn’t implausible. We also know that Hai Gaon was knowledgeable of Hekhalot writings that should at least be considered part of the same thought world as the Shimmush Tehillim. Writings found in the Shimush Tehillim have been found in manuscripts dating from the 12th century. This digital transcription of Shimush Tehillim derives from Elias Klein Békéscsaba’s 1936 compilation. This edition should not be considered a critical text, as earlier editions certainly exist. Not all of the Psalms are identified as having a particular theurgical use. . . .