Reference:
Jung, E. and Von Franz, M. L. (1970) The Grail Legend. English Translation, Princeton University Press, Princeton NJ

p88-89. “…the latter (the sword) symbolizes not only the separating and discriminating aspects of the intellect, but also the judging, wrathful intervention of God in earthly affairs. …
The sword signifies that life-urge which leads to the recognition of the Self.”