Torah Temimah cites Bava Metzia 48a.
“Or oppresses his fellow” — for example, when he designated a vessel against the wage he is withholding.
Diyuk of identified security for oshek — designated vessel required.
Mere unpaid wages without a designated item do not generate asham gezeilot on denial under oath. Only when a specific vessel has been set aside against the wage does the denial parallel a deposit denial and trigger the offering.