The idiom 三生有幸 is formed by sequentially combining four characters: 三 (three), 生 (life), 有 (to have), and 幸 (luck). It originates from Buddhist context, where 三生 specifically refers to the three lifetimes, past, present, and future. The phrase literally means "to have luck in three lives", creating a fixed compound that expresses exceptional fortune across these existences.