2 Samuel 8:18 - Wesley's Explanatory Notes

Cherethites, &c. — The Cherethites and Pelethites were undoubtedly soldiers, and such as were eminent for their valour and fidelity. Most probable they were the king's guards, which consisted of these two bands, who might be distinguished either by their several weapons, or by the differing time or manner of their service. They are supposed to be thus called either, first, from their office, which was upon the king's command to cut off or punish offenders, and to preserve the king's person, as their names in the Hebrew tongue may seem to imply. Or, secondly, from some country, or place to which they had relation. As for the Cherithites, it is certain they were ether a branch of the Philistines, or a people neighbouring to them, and so might the Pelethites be too, though that be not related in scripture. And these Israelites and soldiers of David might be so called, either because they went and lived with David when he dwelt in those parts or, for some notable exploit against, or victory over these people.