They'll Know We Are Christians
"They'll Know We Are Christians" is a Christian hymn written in the 1960s by Catholic priest Fr. Peter Scholtes.
The title of the song may originate from John 13:35: "By this shall all men know that ye are my disciples, if ye have love one to another", Young's Literal Translation, or from a phrase that non-believers used to describe Christians believers of early Church: "Behold, how they love one another".
The song was released on an LP of the same name featuring the congregation of Fr. Scholtes' church, St. Brendan's on the south side of Chicago.