I am violating my oath
At least one argument has been put forth that this oath is not the Pledge of the Order that Egderus refers to a few lines later, but rather a secret oath to an unknown organization or fellowship that he joined near the end of his life. It is of course tempting to speculate that it might be the Fellowship that Egderus dismissively mentions in his public memoirs, but there is absolutely no evidence to support its existence whatsoever.