Everyone who hates his brother is a murderer, and you know that no murderer has eternal life remaining in him. The way we came to know love was that he laid down his life for us; so we ought to lay down our lives for our brothers (and sisters). (1 Jn 3:11-21)
https://bible.usccb.org/bible/readings/010523.cfm
At Christmas we hear a lot about love. Love is fine until it begins to cost us. But it is precisely in what Christ has done for us by laying down his life for us that we learn what love truly is. Saint John Neumann (1811-1860) was the immigrant bishop of Philadelphia, the “City of Brotherly Love.”