Related for Shevuot 76:26

ת"ר שבועת הדיינין אף היא בלשונה נאמרה

The law is in accordance with the view of Raba, for he did not hold any [sacred] object in his hand; but the law is not in accordance with the view of R'Papa, for he held a [sacred] object in his hand. The oath [must be taken] standing; a disciple of the wise [may take it] sitting. The oath must be administered with a Sefer Torah,<span class="x" onmousemove="('comment',' Though if it has already been administered with tefillin it is effective; but a Sefer Torah is required in the first instance .');">⁵³</span>

Tosefta Sotah