Swearing in / vow

Source: TW

This occidental custom of swearing by a religious text is interoperable among Abrahamists – after all their texts are conceptually equivalent across them. However, it raises interesting questions for H. Old H would not swear by a text but by their foot (e.g., in the rAmAyaNa).

But if H had to chose a text which one would it be? I’d probably do so on a vaidika saMhitA, ideally one I’ve studied.

But would say a saiddhAntika shaiva chose the nishvAsa-saMhitA, etc.