Talmud for Sanhedrin 10:1
כָּל יִשְׂרָאֵל יֵשׁ לָהֶם חֵלֶק לָעוֹלָם הַבָּא, שֶׁנֶּאֱמַר (ישעיה ס) וְעַמֵּךְ כֻּלָּם צַדִּיקִים לְעוֹלָם יִירְשׁוּ אָרֶץ נֵצֶר מַטָּעַי מַעֲשֵׂה יָדַי לְהִתְפָּאֵר. וְאֵלּוּ שֶׁאֵין לָהֶם חֵלֶק לָעוֹלָם הַבָּא, הָאוֹמֵר אֵין תְּחִיַּת הַמֵּתִים מִן הַתּוֹרָה, וְאֵין תּוֹרָה מִן הַשָּׁמָיִם, וְאֶפִּיקוֹרֶס. רַבִּי עֲקִיבָא אוֹמֵר, אַף הַקּוֹרֵא בַסְּפָרִים הַחִיצוֹנִים, וְהַלּוֹחֵשׁ עַל הַמַּכָּה וְאוֹמֵר (שמות טו) כָּל הַמַּחֲלָה אֲשֶׁר שַׂמְתִּי בְמִצְרַיִם לֹא אָשִׂים עָלֶיךָ כִּי אֲנִי ה' רֹפְאֶךָ. אַבָּא שָׁאוּל אוֹמֵר, אַף הַהוֹגֶה אֶת הַשֵּׁם בְּאוֹתִיּוֹתָיו:
All of Israel have a share in the world to come, viz. (Isaiah 60:12): "And your people, all righteous, forever shall inherit the land, the sprout of My plantings, the work of My hands, to be glorified." [("All of Israel have a share:") Even those who were executed by beth-din for their wickedness have a share in the world to come. The "world to come" here is the world after the resurrection, when the dead are destined to rise and to stand in their bodies and souls in eternal life, like the sun, the moon, and the stars, as stated in the Gemara in this chapter: "The dead that are destined to arise do not return to their dust." And in the world to come there is no eating or drinking even though there is a body; but the righteous sit with their crowns on their heads and bask in the Divine radiance. And because not all Jews are equal in it, but the greater (is positioned) according to his higher eminence, and the lesser according to his lower eminence — for this reason it is taught "they have a share."] And these do not have a share in the world to come: one who says that there is no resurrection according to the Torah [The Gemara states: "Why all this? It was taught: He denied the resurrection; therefore, he has no share in the resurrection." From here I derive that the "world to come" of this Mishnah is not the world where the souls abide at this time, but the world of the resurrection, as I have explained.], one who says that the Torah is not from Heaven, and an apikores (a heretic) [one who demeans Torah scholars, and, it goes without saying, one who demeans the Torah itself.] R. Akiva says: Also, one who reads in the "outer (i.e., interdicted) books" [books of heresy, such as those of Aristotle the Greek and his colleagues. Included in this is one who reads the chronicles of idolatrous kings, romantic poetry, and literature of indulgence (of the passions), which make neither for wisdom nor benefit, but only for loss of time], and one who utters as an incantation over a wound (Exodus 15:26): "All the sickness which I placed in Egypt, I will not place in you, for I am the L rd who heals you." [It is only when he spits that he has no share in the world to come, the Name of Heaven not to be mentioned over spittle.] Abba Shaul says: Also, one who pronounces the Name [the tetragrammaton] as it is written.