藥師經疏 1.102

1.102

經。第二橫者王法所殺　二枉被王刑。此人壽命是不定業。亦是殺生增上果故。涅槃經云。殺生之人得兩種報。一者短命。二者多病。若遇順緣修福等資助不受王戮得壽命長。若不修福曩昔殺緣則被王害不得長壽故名橫死。

Sūtra: "The second untimely death is being executed by the king's law."
Two: unjustly suffering royal execution. This person's lifespan is indefinite karma, and it is also the dominant result (adhipati-phala) of taking life. The Nirvāṇa Sūtra says: "A person who takes life incurs two kinds of retribution: first, a short lifespan; second, much illness." If they meet supportive conditions such as cultivating merit to aid them, they will not suffer execution by the king and will obtain a long life. If they do not cultivate merit, the past conditions of killing lead to being executed by the king and not obtaining a long life; hence it is called an untimely death.