When people speak of Bushido, they often quote the words 'If a lord is not enough as a lord, his vassals should be loyal', but this idea did not come to fruition until the Edo period, when the idea of Bushido matured.
なお、武士道を語るとき「君、君たらずとも、臣、臣たるべし」といった言葉がしばしば言われるが、これは江戸時代の武士道成熟期には見られなかった考え方である。