Parashas Vayikra · Aliyah 7 · Passuk 1
Chabad.org — English translation + Rashi
Torah Temima points to Shevuot 30a–35a / Toras Kohanim on the silent witness.
E-Daf / Tsurras Hadaf
PDF of the daf / source
English: He hears the voice of an imprecation, and he is a witness… if he does not tell, he shall bear his iniquity.
Chatat for shevu’at ha-edut — failure to testify after a formal adjuration.
One who knows testimony and, after a public oath/curse demanding witnesses, does not come forward, bears his sin and is liable for the oleh ve-yored (or related) process of this chapter.