(Ibid. 6) "Lest the avenger of blood pursue the slayer": This tells me (that he must flee them) only if there is a pursuer and a redeemer. Whence do I derive (the same for an instance) where there is a pursuer but no redeemer, a redeemer but no pursuer, or neither a pursuer or a redeemer? From (the repetition of) "slayer" (verse 4), "slayer" (here), (i.e., in any instance).
(Ibid. 6) "his heart being hot": This tells me only of one (a pursuer) whose heart is "hot." Whence do I derive (the same for) a father pursuing his son or a son pursuing his father? From (the repetition of) "slayer," "slayer."