en_tn_lite_do_not_use/2co/01/23.md

as witness to my soul

The word "soul" here is a metonym for the whole person. Alternate translation: "as witness for me" or "to testify for me" (See: rc://en/ta/man/translate/figs-metonymy)

so that I might spare you

"so that I might not cause you more suffering"