do someone a good turn

• 做有利于某人的事；作好事；为某人效了一次劳

do someone a good turn的用法和样例：

例句

1. There is no amount of good works we can do to save ourselves from being eternally separated from God.
   我们不可能通过做好事来拯救自己，挽救自己不会永远与神分离。