CIL 6.29609, 5–6
cinis sum; cinis terra est; terra dea est; ergō ego mortua nōn sum.
Textbook notes:
Shelmerdine introduces both sum and terra in ch. 5. Dea is also already known. Only cinis probably really needs to be provided.
Wheelock has dea in 6 and terra in 7, which also introduces 3rd decl. nouns (although not cinis). Present of sum already in ch. 4.
Appears in By Roman Hands (#7).
Cf. Epicharmus (Bergk, Poet. Lyr. Graec. 2.239)
εἰμὶ νεκρός, νεκρός δὲ κόπρος, γῆ δ’ ἡ κόπρος ἐστιν·
εἰ δέ τε γῆ θεός ἐστ’, οὐ νεκρός, ἀλλὰ θεός.
I am a corpse and a corpse is dirt, and dirt earth; but if the earth is a God, a God am I and not a corpse. (Tr. J. Edmonds)