Jubilate Agno (Latin: "Rejoice in the Lamb") is a religious poem by Christopher Smart, and was written between 1759 and 1763, during Smart's confinement for insanity in St. Luke's Hospital, Bethnal Green, London. The poem was first published in 1939, under the title Rejoice in the Lamb: A Song from Bedlam, edited by W. F. Stead from Smart's manuscript, which Stead had discovered in a private library.
A "Commission of Lunacy" was taken out against Christopher Smart, and he was admitted in St. Luke's Hospital on May 6, 1757 as a "Curable Patient" by his wife Anna's stepfather John Newbery. It is possible that Smart was confined by Newbery over old debts and a poor relationship between the two. Regardless, there is evidence that an incident took place in St. James’s Park in which he "routed all the company" (Jubilate Agno B89) and this incident may have provoked his being locked away.
During this time, Smart was left alone, except for his cat Jeoffry and the occasional gawker. It is very possible that he felt "homeless" during this time and surely felt that he was in a "limbo… between public and private space". He had nothing else but to turn inwards and devote himself to God and his poetry. No specifics are known about Christopher Smart's day-to-day activities, and he was released from the asylum on January 30, 1763, but his poem was not to be published until 1939.
Jubilate Agno is divided into four fragments labeled "A", "B", "C", and "D". The whole work consists of over 1,200 lines: all the lines in some sections begin with the word Let; those in other sections begin with For. Those in the series beginning with the word "Let," associated names of human beings, mainly biblical, with various natural objects; and those beginning with the word "For" are a series of aphoristic verses.
Editing the work in 1950, W.H. Bond found that, "The poem was intended as a responsive reading; and that is why the Let and For sections [of the manuscript] are physically distinct while corresponding verse for verse. Smart's plan was to arrange the Let and For passages opposite one another antiphonally, following a practice of biblical Hebrew poetry, and that the present MS. represents less than half of Smart's original plan for the poem."
Although the original manuscript divided the "Let" and "For" verses onto opposing sides of the manuscript, Karina Williams claims that "Dr W. H. Bond then discovered that some of the LET and FOR folios were numbered and dated concurrently, and that these chronologically parallel texts were further connected by verbal links." Reinforcing this view of a parallel between the two sides is the fact that Christopher Smart's influence, Robert Lowth and his Lectures on the Sacred Poetry of the Hebrews, spends a large portion of his work exploring the "parallelism" found in "Hebrew verse." In Karina Williamson's 1980 edition, she made an editorial decision and combined the "Let" and the "For" and then justified this combining the two sides to follow each other based on Bond's claims.