An object used to make an impression (usually on clay or wax) that indicated ownership, authenticity, or agreement. Ancient seals consisted of a piece of hard material (stone, ivory, or wood) having engraved letters or designs in reverse. They were made in various shapes, including cones, squares, cylinders, scarabs, and animal heads. (Regarding signet or seal rings, see RING.) Those in the form of a cylinder commonly measured between 2 and 4 cm (0.75 to 1.5 in.) in length. When a cylinder that was engraved on its curved surface was rolled on moist clay, it produced a continuous impression in relief. Often cylinder seals were pierced through from end to end and thus could be suspended from a cord.

Religious symbols, as well as plants, animals, and simple scenes, are among the things depicted on Egyptian and Mesopotamian seals. The Babylonian “Temptation” Seal (British Museum) shows a tree with a man seated on one side and a woman on the other, and behind the woman is an erect serpent. Often seals gave the owner’s name and his position. For example, one seal found in Palestine reads, “Belonging to Shema, the minister of Jeroboam.”​—The Biblical World, edited by C. Pfeiffer, 1966, p. 515.

Seal impressions could indicate ownership or authenticity and could prevent tampering with documents or other things that were sealed, including bags, doors, and tombs. (Job 14:17; Da 6:17; Mt 27:66) When the prophet Jeremiah purchased a field, the copy of the deed bearing the signatures of witnesses was sealed, but a second copy was left open. Perhaps the sealing was done by folding the deed closed, tying it with a cord, and then putting a lump of wax or other soft substance on the cord and impressing the soft material with a seal. If later any question would arise about the accuracy of the open copy, the deed that had been sealed before witnesses could be produced. (Jer 32:10-14, 44) A person entrusted with the king’s seal could issue official decrees, the seal impression stamping the decrees as authentic. (1Ki 21:8; Es 3:10, 12; 8:2, 8, 10) Affixing one’s seal to a document could signify an acceptance of the terms contained therein. (Ne 9:38; 10:1) Numerous ancient jar handles with seal impressions on them have been found. Some of these seal impressions identified the owner of the jars and their contents; others gave an indication of the quantity or quality of the contents.

Figurative Use. The actual uses for seals provide the basis for a number of figurative expressions found in the Bible. It was foretold that the Messiah would “imprint a seal upon vision and prophet.” This is because, by fulfilling the prophecies, the Messiah would stamp them as authentic and inspired of God. (Da 9:24; compare Joh 3:33.) In the sense of a mark of possession, or ownership, Abraham received circumcision as a “seal” of the righteousness that he had. (Ro 4:11) Since the apostle Paul had helped many Corinthian Christians to become believers, they served as a seal confirming the genuineness of his apostleship. (1Co 9:1, 2) First-century Christians are spoken of as being “sealed” by means of holy spirit, which is an advance token of their heavenly inheritance. (Eph 1:13, 14; 4:30) The seal signifies their being God’s possession (2Co 1:21, 22) and shows that they are truly in line for heavenly life. The book of Revelation shows the number finally sealed to be 144,000.​—Re 7:2-4; 9:4.

The Bible speaks of something that is closed, hidden, or secret as being sealed. Prophetic messages were “sealed” during the time they were not understood. (Da 12:4, 9; Re 5:1; 22:10; compare Isa 8:16; 29:11.) And Jehovah is said to ‘put a seal around stars,’ evidently meaning that he hides them from view by means of clouds.​—Job 9:7.