为了【wèile】

为了 gives the goal of an action. The purpose comes first, with 为了, and the action that serves it follows.

The purpose can be a noun: 为了 + person is "for the sake of" them.

Purpose at the end: 是为了

English puts the purpose last: "I came to Beijing to study Chinese". Chinese can do that only with 是为了: the action, then 是为了, then the goal.

• × 我每天跑步为了身体健康 → 为了身体健康，我每天跑步 / 我每天跑步是为了身体健康

为了 or 因为

为了 looks forward to a goal; 因为 looks back at a cause. Something that happened to you, like rain or illness, is a cause.

• × 为了下雨，我们没去公园 → 因为下雨，我们没去公园

A negative goal works with 为了不: "so as not to".