Here's the one Dani mentioned. Most Unity Churches use it in their services. It is my understanding that the people who wrote it were members of Unity or another metaphysical org. BTW, the St. Francis Prayer song is in the DT.

Let There Be Peace On Earth,
and let it begin with me.
Let There Be Peace On Earth,
the peace that was meant to be.

With God as our Fa - ther,
broth - ers all are we,
Let me walk with my broth-er,
in per-fect har - mo - ny.

Let peace be - gin with me
let this be the mo - ment now,
With ev-'ry step I take,
let this be my sol - emn vow,

To take each mo - ment and live each mo - ment
in peace, e - ter - nal - ly.
Let There Be Peace On Earth,
and let it be - gin with me.

Circa 1955
Words and Music by Jill Jackson and Sy Miller