Charles Ellicott Commentary John 13:23

"There was at the table reclining in Jesus` bosom one of his disciples, whom Jesus loved." — John 13:23 (ASV)

Now there was leaning on Jesus’ bosom.—Leonardo’s picture is misleading in one respect: like most paintings of the Lord’s Supper, it has not depicted the way the guests reclined rather than sat at the table. Each leaned on his left arm, leaving the right arm free. His feet were stretched out behind the guest on his right, and the back of his head was near the bosom of the guest on his left (compare Note on John 13:25). The Jews followed this Persian method of reclining on couches at meals from the time of the Captivity. This method of eating the Passover, in particular, held special significance, as it denoted security and possession of the Promised Land, in contrast to the posture of one undertaking a journey, which was part of the original institution (Exodus 12:11).

One of his disciples, whom Jesus loved—that is, John himself. (John 21:7; John 21:20–23, and Introduction, p. 375.) The same designation also occurs in John 19:26.