for the sake of something or someone

You and your friend happen to like the same girl. Neither of you planned on falling in love with the same girl. It just happened. Now you have to decide what you're going to do about it in order to benefit both of you and protect the friendship. After a few conversations, you've decided that for the sake of your friendship you two should forget that specific girl and look for someone else. You both know it's a tough decision to make, but for the sake of your friendship, which is the most important thing now, no one should date the girl. When you do something for the sake of something or someone, you do it for the purpose or benefit of something or someone. In that case, for the benefit of your friendship.

Now imagine you're going through financial problems at home and as a way to sustain your family you have to work two jobs. During the day you work as an English teacher, and during the night you moonlight as a security guard. When someone asks you why you've been working so much lately, you answer: I have to earn a living for my family's sake. In other words, you have to work two jobs in honor of your family, for your family's good or benefit. I hope this is helpful. Talk to you next time!