The song "They’ll Know We Are Christians (by our Love)," was written in 1966 by Father Peter Scholtes, a 30-year old parish priest at St. Brendan Church on Chicago’s south side. He was searching for a song his youth group could perform at an upcoming ecumenical, interracial event. Finding none, he wrote "They’ll Know" in one day. It is based on John 13:35: “By this everyone will know that you are my disciples, if you have love for one another.”
We are one in the Spirit, we are one in the Lord;
We are one in the Spirit, we are one in the Lord;
And we pray that all unity will one day be restored.
And they'll know we are Christians by our love, by our love,
yes, they'll know we are Christians by our love.
During this Easter season, may each of us hear Jesus’ call to love, and may we allow that message to be the inspiration for our lives, thereby living our faith in action.
(from https://www.youtube.com/results?search_query=%22Our+Love%22 )