This is my commandment, that you love one another as I have loved you. Greater love has no one than this, that someone lay down his life for his friends. You are my friends if you do what I command you. No longer do I call you servants, for the servant does not know what his master is doing; but I have called you friends, for all that I have heard from my Father I have made known to you.
(John 15:12-15 ESV)
I go to mass every week hoping to hear beautiful things. But this reading, in particular, sums up the whole story, and gives meaning to life!