Instrumental Duet,Piano Instrumental Duet,Piano,Viola,Violin - Level 2 - Digital Download SKU: A0.623541 Composed by Spiritual. Arranged by Stephen DeCesare. Christian,Easter,Sacred,Spiritual. Score and parts. 12 pages. Exultet Music #4359147. Published by Exultet Music (A0.623541). Vibrant arrangement of the very popular Spiritual Somebody's Knockin' At Your Door which has been freshly arranged as a duet for Violin and Viola with Piano accompaniment. Accessible and appropriate for any church or concert setting.  .