Hermes appears to Aegisthus and informs him of the consequences which must be involved in this act. When he perpetrates the act notwithstanding, his fall is caused by himself.
Otto argues that Aegisthus is the Homeric exemplar of self-caused catastrophe, wherein divine warning is fully delivered yet consciously disregarded, making the transgressor the author of his own fate.
, The Homeric Gods: The Spiritual Significance of Greek Religion, 1929thesis