Everything about "pox leber" as a minced oath, and an earlier source.

[MarcoP]

Hi Koen, thank you for finding this interesting passage!

I extended and slightly corrected my previous transcription. A few words are missing and it certainly isn't 100% correct.

Ex quo patet primo / quod valde reprehendendi sunt qui / jurant ad omnia verba, et false per / creaturas ut "poxplwt samerpox umgel", putando se non peccare, non obligari, ... ex dictis ... graviter / errant.  Secundo patet plus / sunt reprehendendi qui iurant per turpes /  creaturas similiter se non putantes obli/gari ut "pox grmt poxgrint* poxlaus / zais", quod in istis omnibus creator earum / relucet, ... sunt per ista falsum / iurant sunt periuri et peccant / graviter. Tertio patet quod ad huc / sunt plus reprehendendi qui iurant / per ea que non sunt nec erunt / putantes se non obligari, sicut / qui dicunt "sam mir pox gamiger / gamer", nullus enim hyrcus habet[?] / supplicium suppliciorum, nec in istis / deus relucet, unde videntur dupliciter / peccare, quod peyorant et quia / invocant testem quod nec in se nec / in eo relucente testificari potest.

In the line starting with "gamer", the "bock" (hyrcus) is explicitly mentioned.

*poxgrint, see next comment

EDIT: I realized that "supplicium suppliciorum" likely translates "gamiger gamer". "Sam mir gamiger gamer" - (if I lie) may I be cursed by bock's (instead of God's) eternal torment.