Beheading

Concise Bible Dictionary:

This was not a form of capital punishment in the Old Testament. Ishbosheth was beheaded by his murderers that his head might be carried to David (2 Sam. 4:7-87For when they came into the house, he lay on his bed in his bedchamber, and they smote him, and slew him, and beheaded him, and took his head, and gat them away through the plain all night. 8And they brought the head of Ish-bosheth unto David to Hebron, and said to the king, Behold the head of Ish-bosheth the son of Saul thine enemy, which sought thy life; and the Lord hath avenged my lord the king this day of Saul, and of his seed. (2 Samuel 4:7‑8)); as Goliath’s head had been carried to Saul. In the New Testament John the Baptist was killed in the Roman manner of beheading with the sword (Matt. 14:1010And he sent, and beheaded John in the prison. (Matthew 14:10); Mark 6:16, 2716But when Herod heard thereof, he said, It is John, whom I beheaded: he is risen from the dead. (Mark 6:16)
27And immediately the king sent an executioner, and commanded his head to be brought: and he went and beheaded him in the prison, (Mark 6:27); Luke 9:99And Herod said, John have I beheaded: but who is this, of whom I hear such things? And he desired to see him. (Luke 9:9)). In Revelation 20:44And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years. (Revelation 20:4), those “beheaded” for the witness of Jesus, may be killed in other ways, for the word πελεκίζω signifies “to cut with an ax,”‘ having no particular reference to the head.

From Manners and Customs of the Bible:

2 Kings 10:88And there came a messenger, and told him, saying, They have brought the heads of the king's sons. And he said, Lay ye them in two heaps at the entering in of the gate until the morning. (2 Kings 10:8). There came a messenger, and told him, saying, They have brought the heads of the king’s sons. And he said, Lay ye them in two heaps at the entering in of the gate until the morning.
Beheading enemies is a very ancient custom. Thus David cut off the head of Goliath and carried it to Saul (1Sam. 17:51,5751Therefore David ran, and stood upon the Philistine, and took his sword, and drew it out of the sheath thereof, and slew him, and cut off his head therewith. And when the Philistines saw their champion was dead, they fled. (1 Samuel 17:51)
57And as David returned from the slaughter of the Philistine, Abner took him, and brought him before Saul with the head of the Philistine in his hand. (1 Samuel 17:57)). So also the Philistines cut off the head of Saul (1 Sam. 31:99And they cut off his head, and stripped off his armor, and sent into the land of the Philistines round about, to publish it in the house of their idols, and among the people. (1 Samuel 31:9)). Layard found at Nineveh representations of scenes which well illustrate the text. Heads of slain enemies are collected and brought to the king, or to the officer appointed to take account of their number. Morier, in his narrative of his second journey through Persia, states that prisoners have been known to be put to death in cold blood in order to increase the number of heads of the slain which are deposited in heaps at the palace gate. Many such heaps of heads are piled up in Persia. Sir William Ousely, who was in Persia in the early part of this century, saw the remains of some of these heaps on which the skulls seemed to be stuck together in a mass of clay or mortar. Similar accounts are given by later travelers.

Related Books and Articles:

343. Enemies Beheaded