Torah calls Ishmael a wild man...
I think that is what you are thinking about...
http://www.meaningfullife.com/currentevents/sept11/IshmaelCOLON_How_Does_it_EndQUESTION.phpIshmael did teshuvah (Rashi Chayei Sarah, Genesis 25:9)
They [Ishmael’s descendants] overran all their brethren (25:18)
On the face of all his brethren he will dwell (16:12)
On the face of all his brethren he fell (25:18)
While Abraham was alive he [Ishmael] dwelled; after Abraham’s death he fell (Rashi)
‘On the face of all his brethren he fell’ is followed immediately by ‘and these are the children of Isaac,’ to teach us that the son of David, who stems from the children of Isaac will sprout when Ishmael will fall at the end of days, then will sprout the son of David, who stems from the children of Isaac (Baal HaTurim end of Chayei Sarah)
He [Ishmael] will be a wild man. His hand will be against everyone, and everyone’s hand will be against him (Genesis 16:12)
Abraham 1948-2123
Ishmael 2034-2171
Isaac 2048-2228
Jacob 2108-2255