'In the Hereafter Abraham will sit at the entrance of Gehinnom and will not allow any circumcised Israelite ot descend into it. As for those who sinned unduly, what does he do to them? He removes the foreskin from children who had died before circumcision, places it upon them and sends them down to Gehinnom.'
'Israelites who are circumcised will not descend to Gehinnom. So that heretics and the sinners in Israel shall not say, "Inasmuch as we are circumcised we will not go down to Gehinnom," what does the Holy One, blessed be He, do? He sends an angel who extends the foreskin and they descend to Gehinnom.'
'they who are sentenced for a time in Gehinnom ... Abraham our father comes and takes them out and receives them, with the exception of an Israelite who had intercourse with a gentile woman or disguised his circumcision for the purpose of concealing his identity'
From the Gemara and Midrash.
