#151. If One Errs and Puts on Rabbeinu Tam Tefilin Instead of Rashi…
It is very likely that people who put on both Rashi and Rabbeinu Tam tefilin every day will at some point inadvertently put on the Rabbeinu Tam instead of Rashi and make a brocho, blessing, on it. Some have a tradition that this error will always happen at some point to an individual who is scrupulous in wearing both pairs daily, and that one should rest assured that the error has been orchestrated from Above in order to provide him with the privilege and merit of making a brocho on Rabbeinu Tam tefilin, a pair that we ordinarily do not make a brocho on. There are various opinions about what is to be done in such a case. The accepted opinion is that if he remembers immediately after he put on the Rabbeinu Tam tefilin without having made any interruption, he should put on the Rashi tefilin right away without making a new brocho. This applies only to someone who always wears both pairs, and both pairs were in front of him when he said the brocho. However, if he interrupted, even by saying words of davening, then he should take off the Rabbeinu Tam tefilin and put on the Rashi tefilin with a brocho. Nonetheless, since there is difference of opinion among poskim, it is recommended that in order to avoid this questionable situation one should make a definite interruption, such as going to the bathroom; after doing so, all poskim agree that he can then make a brocho on the Rashi tefilin. It is recommended that after davening one should put back on the Rabbeinu Tam tefilin and recite the customary prayers, if he has not done so yet.