When he eventually decided to make a full album of covers, Mr. Gabriel ruled out drums and guitars. He went on to renounce the funk, soul and world-music elements that have filled his past albums. He was determined to strip the songs down to the bare melody and lyric.(source)
Through the use of voice and orchestra, he provides his own tangent.
He also inverted his usual recording process. Instead of writing and arranging songs before completing the vocals, for “Scratch My Back” the vocals came first, recorded on sparsely accompanied demos. The performances are slow and somber, dropping to a whisper or building to a breaking ululation. Mr. Gabriel’s voice sounds desperate and exposed, clinging to the melody like a life raft. “As you get older, some top notes drop off and bottom notes appear, which I quite like,” Mr. Gabriel said. “You listen to Leonard Cohen or Johnny Cash, and you see the advantage of the lower end.”(source)