In a new and precedent-setting halachic ruling published in the recent edition of the Tehumin journal, Rabbi Yaakov Ariel rules that one can wrap tefillin (phylacteries), wave the Four Species on Sukkot, and recite the Priestly Blessing with bionic prosthetic limbs.
Rabbi Ariel rules that halachically, the prosthetic, which uses sensors and motors that are synchronized with the body's movements, is considered part of the human body.
In addition, the ruling allows the use of a bionic limb on Shabbat, and states that its operation does not constitute a Torah prohibition since no electric circuit is being closed directly, but rather it is being operated indirectly. Rabbi Ariel also says it is permitted to reassemble the prosthetic after sleeping, which entails rebooting it, since it is a basic need and it is not prohibited by the Torah.
The ruling is among a series of actual articles published in the new edition of Tehumin under the title "The Swords of Iron War," dedicated to halachic issues that came up during the war, from identifying bodies to complex medical conditions.
The Zomet Institute of Halacha and Technology, which publishes the journal, noted that the ruling is innovative, allowing wounded soldiers and terror victims with bionic limbs to serve G-d fully. According to the institute, this reflects a broader trend of adapting halacha to the technological and medical realities of our time — including in matters of Shabbat, purity, and life itself.