http://www.nypost.com/seven/04172007/news/nationalnews/va__tech_killer_revealed_nationalnews_.htm
Sources told the Tribune that the words “ISMAIL AX” were also found written in red ink on the inside of one of Cho’s arms.
The reference may be to the Islamic account of the Biblical sacrifice of Abraham, where God commands the patriarch to sacrifice his own son. Abraham begins to comply, but God intervenes at the last moment to save the boy.
In the Jewish and Christian traditions, the son is Isaac, father of the Jewish people; in Islam, it is his brother, Ismail (Ishmael in Hebrew).
Abraham uses a knife in most versions of the story, but some accounts have him wielding an ax.
A more obscure reference may be to a passage in the Koran referring to Abraham’s destruction of pagan idols; in some accounts, he uses an ax to do so.