Epistle to the Philippians in Wikipedia
The Epistle of Paul to the Philippians, usually referred to
simply as Philippians, is the eleventh book in the New
Testament. Biblical scholars agree that it was written by St.
Paul to the church of Philippi. This authentic Pauline letter
was written c 62.Paul's composition of Philippians is
"universally accepted" (Beare, p. 1) by the academic
community, both ancient and modern. It is possible that the
kenosis passage in Philippians 2:5-11 may have been a
Christian hymn that Paul quoted.