ἐσφράγισεν [1 verse] (3rd sg aor ind act) "Sealed" is from sphragizo, which means "to close," "to close with a seal," "to authenticate [a document with a seal]," "to close up [as with a seal]," and "to set a seal of approval upon." - The final section of the verse says that God has "sealed" Christ. However, the purpose of seals in Christ era was to authenticate or approve of something. A "seal" was the mark of a person in authority. So the Father has authenticated or approved the Son to give people the strengthening meat that leads to eternal life.