Bosom buddy/friend In english explanation

 This turn of phrase for denoting a very dear associate is found in both the Old and New Testaments. Nathan says it “lay in his bosom and was unto him as a daughter” (2 Samuel 12:3), and in the Gospel of St. John, John, often called the “beloved disciple,” is described as the bosom friend of Jesus. In his “Ode to Autumn” John Keats wrote, “Season of mists and mellow fruitfulness, close bosom-friend of the maturing sun.” By this time “bosom friend” was also a euphemism for body lice, and Jonathan Swift’s Polite Conversation (1738) includes the pun, “I’m afraid your Bosom Friends are become your Backbiters.” The alliterative bosom buddy is of later provenance; the word “buddy,” for comrade or chum, dates from the mid-nineteenth century and originated in America.