(set a, set to) seal up, stop

Dictionary of Biblical Words:

This is the indwelling of the Holy Ghost who takes up His abode in every believer, whose body becomes henceforth the temple of the Holy Ghost (1 Cor. 6:19). Christ was sealed as Son of Man for His special work on earth (John 6:27). Believers are sealed (2 Cor. 1:22), after having received the gospel (Eph. 1:13), until the day of redemption (Eph. 4:30), the Spirit then becoming the earnest and pledge of the future inheritance (2 Cor. 1:22). As distinguished from quickening it only is applied to believers, whereas quickening is solely applied in Scripture to sinners, hence always preceding, and always distinct from sealing, though not necessarily distinguishable.

Boyd’s Bible Dictionary:

(little mark). Much used by ancients to authenticate documents and secure packages and doors, the impression being made in clay or wax. Seals were frequently engraved stones set in rings (Gen. 41:42; Job 38:14; Jer. 32:10; Matt. 27:66).

Concise Bible Dictionary:

Seal Ring (1600-1700)
Stones on which words, letters, or symbols are engraved. Anciently these were pierced, and by a cord or chain were hung from the arm or the neck, or they were set in rings and worn on the finger. The design was impressed on pieces of clay which were attached to official documents, which in the East are not considered authentic without being sealed (Ex. 28:11; Esther 8:8,10; Job 38:14; Dan. 6:17). The seal was also used to ensure security, or to preserve the sanctity of things not to be revealed (Isa. 29:11; Dan. 12:4,9; Matt. 27:66; Rev. 20:3; Rev. 22:10).
A covenant was sealed by Nehemiah and those with him (Neh. 10:1). The believer, in crediting what God says of man, and of God’s salvation, virtually attaches his seal (vouches for the fact) that God is true (John 3:33). “The foundation of God standeth sure, having this seal, The Lord knoweth them that are His [God’s side]; and, Let everyone that nameth the name of the Lord depart from iniquity [man’s side]” (2 Tim. 2:19). This is an illustration of a double-seal turning on a pivot, of which either side could be used.
The roll in Revelation 5 had seven seals, so arranged that by breaking one seal a certain portion could be unrolled; and each seal was broken in succession until the whole was revealed.

Strong’s Dictionary of Greek Words:

Greek:
σφραγίζω
Transliteration:
sphragizo
Phonic:
sfrag-id’-zo
Meaning:
from 4973; to stamp (with a signet or private mark) for security or preservation (literally or figuratively); by implication, to keep secret, to attest
KJV Usage:
(set a, set to) seal up, stop