Oath-swearing is an important aspect in the hierarchical system of the Kilrathi Empire.
A Kilrathi is oathsworn to a group or a cause; specifically retainers and liegemen swear fealty to a Thrak'hra (clan Lord), and soldiers to a khantahr. Failure to serve the cause or individual one is sworn to (eg. refusal to follow orders), is considered oath-breaking and damages one's honor, which is more important than life.
When a Kilrathi submits himself to another, he speaks the ritual words, binding his life to that of his lord, and baring his throat expecting either to accept his oath by performing the ceremonial actions and words, or to dismiss him by slicing his throat with his claws.
The oath of fealty means that the oathsworn, for all his and his descendants's lives, is to be commanded by a Lord and the Lord's hrai, and to obey their orders without question. The oathsworn is supposed to defend the lord's honor and life with his own. The honor-code also protects the oathsworn from being abused or exploited, or being used against his Lord. He won't perform even rudimentary actions without the knowledge or permission of his lord, because he can't know for certain that it is harmless.
A lord can offer his retainer to another one as a gift, who also performs the ceremony and becomes the new liege-lord; however, unless the first lord (the overlord) takes back the oath, the retainer's first loyalty would always be to him. The overlord can command the retainer as long as this doesn't contradict the will of the liege-lord; the overlord can't command the retainer to disobay his liege-lord.