Tanu d'by Eliyahu.
Rabbi Berachia saith, "In order that the Minim, apostates, and wicked Israelites might not escape hell on account of their circumcision, the Holy One—blessed be He!—sends an angel to undo the effects of it, and they straightway descend to their doom. When Gehenna sees this, she opens her mouth and licks them." This is the purport of (Isa. v. 14), "And she opened her mouth to those without law" (i.e., to those without the sign of the covenant).
Midrash Rabbath Shemoth, chap. 19.
"God hath also set the one over against the other" (Eccles. vii. 14), i.e., the righteous and the wicked, in order that the one should atone for the other. God created the poor and the rich, in order that the one should be maintained by the other. He created Paradise and Gehenna, in order that those in the one should deliver those in the other. And what is the distance between them? Rabbi Chanina saith the width of the wall (between Paradise and Gehenna) is a handbreadth.
Yalkut Koheleth.
"Those passing through the valley of weeping make it a well; also blessings shall cover the teacher" (Ps. lxxxiv. 6, A.V.). "The valley of weeping" is Gehenna. "Make it a well," for their tears are like a well or spring. "Also blessings shall cover the teacher." Rabbi Yochanan saith, "The praises of God that ascend from Gehenna are more than those that ascend from Paradise, for each one that is a step higher than his neighbor praises God, and says, 'Happy am I that I am a step higher than the one below me.' 'Also blessings shall cover the teacher,' for they will acknowledge and say, 'Ye have taught well, and ye have instructed well, but we have not obeyed.'"
Yalkut Tehillim, 84.
Those of the house of Eliyahu have taught that Gehenna is above the sky, but some say it is behind the mountains of darkness.
Tanu d'by Eliyahu.
Gehenna was created before Paradise; the former on the second day and the latter on the third.