for the sake of 此在必定是为了自己；为何之故；为了…起见

【例句】
Your attention please: For the sake of the health of you and the others, Please do not smoke in the train.
乘客请注意：为了您和他人的健康，请不要在车厢内吸烟。多谢合作！

For the sake of simplicity, let's divide the discussion into two parts.
为了方便起见，我们把讨论分成两部分。