daf bit: Sanhedrin 55

[cellio]

The mishna teaches: In the trial of one accused of blasphemy, the witnesses were examined using a substitute for the divine name (not the divine name itself). However, this evidence is insufficient to carry out judgment in the case of a conviction, so at the end of the day the judges sent everyone out except the witnesses. They then asked the first witness to say precisely what he heard, invoking the divine name, and then rent their garments when he did so. The second witness then said "I heard that too", not repeating the name, as did the third witness. (55b/56a)

Thus the rabbis balanced the need for accurate testimony with the need to not use the divine name inappropriately.

Comments

[cellio]

And the text here clarifies that you can't sew it back up later. (This is the same sign of mourning as for a parent -- for everyone who's a close-enough relative you rend, but for everyone else you can repair it later. But this is why you'll sometimes see Jewish mourners wearing a black ribbon that has been cut; it's a stand-in for the garment.)