"They'll Know We Are Christians" (also known as "They'll Know We Are Christians By Our Love" or "We Are One in the Spirit") is a Christian hymn written in 1968 by then-Catholic priest Peter Scholtes. It is inspired by John 13:35. It was released on an LP of the same name featuring the congregation of Scholtes' church singing this hymn and others.
The title of the hymn They'll Know We Are Christians By Our Love originates in a phrase that non-believers used to describe Christians believers of early Church: "Behold, how they love one another."
Covers
The song has been covered by a variety of Christian recording artists, including Jars of Clay, Rebecca St. James, and For King & Country, which covered the song for the show "A.D, the Bible Continues."
References
They'll Know We Are Christians Wikipedia(Text) CC BY-SA