【原文】司马牛忧曰：“人皆有兄弟，我独亡。”子夏曰：“商闻之矣：‘死生有命，富贵在天’。君子敬而无失，与人恭而有礼。四海之内，皆兄弟也。君子何患乎无兄弟也?”【译文】司马牛忧伤地说：“别人都有兄弟，唯独我没有。”子夏说：“我听说过：‘死生命中注定，富贵由天安排。’君子(只要)敬业而不犯错误，对人恭敬而有礼貌。四海之内都是兄弟呀。君子担心什么没有兄弟呢?”

The greatest thing you'll ever learn is just to love and be loved in return.

If you're horrible to me, I'm going to write a song about it, and it won't be a good one for you.

When you’re young, you presume there’ll be many people with whom you’ll connect with. Later in life, you realize it only happens a few times.

解析：强调实践的重要性。

对待小人态度严厉，不困难，困难的是让自己不去憎恨厌恶他们；对待君子恭敬谦逊，不困难，困难的是让自己始终以礼相待他们。