Easton's Bible Dictionary (1897)
In the East objects are carried in the bosom which Europeans carry in the pocket. To have in one’s bosom indicates kindness, secrecy, or intimacy (Gen. 16:5; 2 Sam. 12:8). Christ is said to have been in “the bosom of the Father,” i.e., he had the most perfect knowledge of the Father, had the closest intimacy with him (John 1:18). John (13:23) was “leaning on Jesus’ bosom” at the last supper. Our Lord carries his lambs in his bosom,
i.e., has a tender, watchful care over them (Isa. 40:11).
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
BO'SOM . The dress of the Jews was such as allowed them to carry within a fold in the bosom of the robe what could not be carried in the hand. Isa 40:11; Luke 6:38, It was also used to denote a place of rest and security. Hence the term Abraham's bosom is figuratively spoken of as the abode of Lazarus, and means the same as paradise. Luke 16:23; comp. Luke 23:43. To lean on the bosom implied great intimacy. John 13:23. The position of John,
leaning on the bosom of the Saviour, was easy and natural, since the company were reclining at table upon couches, and the back of his head came near the bosom of Jesus, who was on his left. The use of this term, John 1:18, imports the perfect unity of the Father and Son.