Leaning on Jesus’ bosom - This does not mean that he was at that time actually lying on his bosom, but that he occupied a situation next to him at the table, so that his head naturally fell back on his bosom when he spoke to him. See the notes at Matthew 23:6.
Whom Jesus loved - This was doubtless John himself. The evangelists are not accustomed to mention their own names when any mark of favor or any good deed is recorded. They did not seek publicity or notoriety. In this case the appellation is more tender and honorable than any mere name. John was admitted to special friendship, perhaps, because the natural disposition of our Saviour was more nearly like the amiableness and mildness of John than any of the other disciples (Robert Hall). The highest honor that can be conferred on any man is to say that Jesus loved him. Yet this is an honor which all may possess, but which none can inherit without his spirit and without loving him. It is an honor which cannot be won by wealth or learning, by beauty or accomplishments, by rank or earthly honors, but only by the possession of a meek and quiet spirit, which is in the sight of God of great price, 1 Peter 3:4; compare Romans 8:9.