John 13:23. Now there was leaning on Jesus’ bosom one of his disciples, whom Jesus loved.
Reclining on the triclinium, or dinner-bed, the guest lay usually upon his left side, leaving his right hand free to reach the food. See note on Matthew 26:7. His head would thus easily come into contact with the breast of the person on his left. It was in this way that John leaned on the bosom of Jesus while at supper. This is also mentioned in John 13:25; 21:20. A figurative use of the custom referred to is made in Luke 16:22-23; John 1:18.