May one recite a blessing on borrowed tefillin? What about stolen tefillin?

Synopsis

The Mechaber permits blessing on borrowed tefillin (even without the owner's knowledge) but prohibits blessing on stolen tefillin. The Gra extends the prohibition even after the owner despairs and ownership transfers, unlike the Magen Avraham who is lenient about a buyer reciting a blessing.

Early Acharonim
Lenient
Strict
Lesser cited
Major authority

Discussion

Discussion coming soon.

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