The phrase "familiar chorus" refers to a part of a song that repeats several times. It is a section of the song that listeners recognize and can easily sing along to because they have heard it before. Full definition
The words of Harvard geneticist Richard Lewontin join a familiar chorus. (firstthings.com)
Walter Brueggemann, in his collection of addresses entitled Living Toward a Vision, begins by attacking our individualistic «habits of the heart,» typified by the familiar chorus, «I've got the peace that passes understanding down in my heart.» (religion-online.org)