Midrash for Bava Kamma 182:7

אלא תנאי היא דאיכא למ"ד אין אדם רשאי לחבל בעצמו ואיכא מ"ד אדם רשאי לחבל בעצמו

— It must therefore be said that Tannaim differed on this point, for there is one view maintaining that a man may not injure himself and there is another maintaining that a man may injure himself. But who is the Tanna maintaining that a man may not injure himself? It could hardly be said that he was the Tanna of the teaching, And surely your blood of your lives will I require,<span class="x" onmousemove="('comment',' Gen. IX, 5. ');">⁶</span>

Sifrei Devarim