σφραγίζω

to set a seal upon, mark with a seal, to seal, for security from Satan, since things sealed up are concealed (as the contents of a letter), to hide, keep in silence, keep secret, in order to mark a person or a thing, to set a mark upon by the impress of a seal or a stamp, angels are said to be sealed by God, in order to prove, confirm, or attest a thing, to confirm authenticate, place beyond doubt, of a written document, to prove one's testimony to a person that he is what he professes to be