sacredly

And they asserted that they were bound by an oath when the trust was committed to them, for they had all sworn and were bound to carry out the oath sacredly to the letter, that though they were five hundred in number they would not permit more than five men to enter at one time.

And after, the king, as I have already said, had received the explanation of Demetrius on this point, he did homage and ordered that great care should be taken of the books, and that they should be sacredly guarded.