“My holiness is my salvation”
Let’s look at the words holiness and salvation. Holiness indicates purity and wholeness, which are core qualities of creation. Since you are a part of creation—you did not create yourself after all—purity and wholeness are your core qualities as well.
Salvation means release. Release from what? Release from identification with appearances. The course sees the world as an effect. Salvation means release from identification with an effect and restoration to creative principle.
The statement “My holiness is my salvation” is about understanding and experiencing that your innate, inalienable purity and wholeness release you from your identification with the world on the level of appearance and restore your awareness of your true identity. And with that release and restoration the world is released and peace restored.