TT #204 · Parashas Shoftim · Fifth Aliyah · Passuk 19:05
And one who comes with his fellow into the forest to chop wood, and his hand swings with the axe to cut the tree, and the iron slips from the wood and finds his fellow and he dies – he shall flee to one of these cities and live.
Torah Temimah points to Makkot 7b.
TT lemma: וְנָשַׁל הַבַּרְזֶל מִן הָעֵץ.
English: ‘And the iron slips from the wood’ – from the wood that is being split.
Derash on the alternative scenario (Bavli) — the phrase can describe either the head leaving the handle or a glancing blow.
Whether the axe-head leaves the handle or glances from the tree, the result is treated as accidental if the conditions of the verse are met.