thewitchingcow:

The significance of Seth in the Osiris myth may, I think, be summarised as follows. Seth is he who opposes the order of life and death by murdering Osiris, who had to die. The Egyptians have hardly mentioned the motives of his act. Occasionally it is related that Seth excused himself by saying that Osiris had come too near to him and had defied him.

Usually no activities towards Seth are ascribed to Osiris; he is essentially a passive god. Precisely this passivity, however, might be a defiance for Seth.

Perhaps the Pyramid text mentioned above might be understood as signifying that Osiris had appeared to his brother Seth as the god whose essence is death and as he who must die, and that it was this which aroused the aversion and aggression of Seth, whose unbridled zest for life clashes with passivity.

– P. 95 – Seth, God of Confusion, H Te Velde.