What does it mean to be "sealed" (sphragizo) with the Spirit?
Sphragizō (σφραγίζω) means to seal, to mark as owned and secured. "In whom also after that ye believed, ye were sealed with that holy Spirit of promise" (Eph 1:13). The seal is placed at faith and marks the believer as God’s.
What the text states
A seal in the ancient world marked ownership and guaranteed security, a wax seal on a document was both signature and lock. Believers are sealed “unto the day of redemption” (Eph 4:30): the seal lasts until the goal, not until the next failure. The timing is exact, “after that ye believed, ye were sealed”, the seal follows faith, and it is God's own Spirit, so the guarantee is God's.
A seal that could break is no seal; Scripture's seal holds to the day of redemption.
Go deeper
Checked 2026-09-29 by Darren. 45 Scripture citations verified against the KJV rows. Every Strong's number in the wave-3 notes resolved against our own strongs_greek / strongs_hebrew and the lemma matched the form in the file. Wave 3. 45 quoted fragments table-passed against the verses table, all pass. 21 Greek and 3 Hebrew Strong's entries cross-checked against strongs_greek (5,523 rows) and strongs_hebrew (8,674). Three notes, none a form mismatch: (1) G2434 hilasmos is glossed in our table as 'atonement... an expiator', usage 'propitiation', so Strong's own wording is softer than the answer's 'not merely expiation'; Thayer and BDAG carry the propitiation sense and the KJV renders it so. (2) G728 is spelled arrhabon in our table (double rho) against the file's arrabon; the same word, a transliteration convention. (3) our table derives skenoo (G4637) from skenos (G4636), while the answer says it is built on skene (G4633); the three are cognate and skene is the LXX's tabernacle word. One reference in the wave-3 verification notes did not exist: Rev 22:24 (Revelation 22 ends at verse 21). Ruled by Darren 2026-09-29 a typo for Rev 22:17 and corrected in the source file. The hilasmos gloss discrepancy was ruled the same day: the answer stands and is not softened.
wsb.bible/answers/sphragizo