Add +1 to the Space Marine combat resolution score of any assault that takes place within 6" of a sacred standard. However, if the model bearing the standard is slain in close combat, then the enemy model that slew him captures the standard and gets the bonus from then on. It is possible for a standard to change hands several times in a single battle, as long as the model holding the standard is slain in close combat each time.
Sacred Standard
Source: Codex: Space Marines, p. 35