Most modern hymns are penned by Protestants, but one of the best ones from recent decades comes from a Franciscan named Johann Sebastian von Tempelhoff (1928-1997). Tempelhoff was a prolific singer and songwriter under the name Sebastian Temple. Born in Pretoria, South Africa, he was a Scientologist for a time before he converted to Catholicism.

This hymn is based on a traditional prayer attributed to St. Francis of Assisi, though modern scholars usually credit a later Franciscan, Jacopo di Toddi. In English, the prayer reads:
Lord, make me an instrument of your peace. Where there is hatred, let me sow love. Where there is injury, pardon. Where there is doubt, faith. Where there is darkness, light. Where there is sadness, joy.

O Divine Master, grant that I may not so much seek to be consoled, as to console; to be understood as to understand; to be loved as to love; for it is in giving that we receive, it is in pardoning that we are pardoned and it is in dying that we are born to eternal life.
Temple, a resident of California at the time, penned the hymn for a collection for a Franciscan church in Los Angeles:
I wrote so easily and so prolifically that I took for granted that I could write music to the peace prayer of St. Francis. The album’s other twelve songs fell out of my lips and on to a tape recorder very easily and I wrote them in two days. The third day was left for the peace prayer. Though inspirations for all came easily to me, its strange form drove me crazy. I could not come up with anything that sounded like music to my ears. I tried for a whole morning but nothing came. Finally, I was disgusted, looked at the little statue of St. Francis on my shelf and said angrily, “Well, if you want to write it, YOU do it. I can’t.” I got up, went to the kitchen, made a cup of tea and drank it. When I returned to the guitar, I picked it up, had the tape recorder running, and the song fell out of my mouth as it was recorded a few days later.
The text of Temple’s hymn, also known as “Prayer of St. Francis”:
Make me a channel of your peace.
Where there is hatred, let me bring your love.
Where there is injury, your pardon, Lord.
And where there's doubt, true faith in you.

Make me a channel of your peace.
Where there's despair in life, let me bring hope.
Where there is darkness, only light.
And where there's sadness, ever joy.

Oh, Master grant that I may never seek
So much to be consoled as to console,
To be understood as to understand,
To be loved, as to love with all my soul.

Make me a channel of your peace.
It is in pardoning that we are pardoned,
In giving to all men that we receive,
And in dying that we are born to eternal life.
The hymn was a favorite of Diana, Princess of Wales and was performed at her funeral by the choir of Westminster Abbey. (The BBC recording of the funeral service initially didn’t credit Temple or the copyright holder, OCP Publications, until the non-profit religious corporation filed a lawsuit.) On the Diana, Princess of Wales: Tribute album, it is sung by Sinéad O'Connor.

Quotes and background info from Ian Bradley, The Book of Hymns, 1989.