The Philippians are said to share with Paul in the defence and confirmation of the gospel (Phil. 1: 7), that is, in the establishment of its truth at his forthcoming trial. Possibly he is optimistic about an acquittal which will strengthen the position of the Church of Philippi.
Confirmation in the sense of a sacramental rite, though sometimes traced to the teaching of the apostles, as in the Preface to the service of confirmation in the Anglican Book of Common Prayer, is in fact not known in the NT as a rite supplementing baptism by water. When it is recorded that the apostles at Samaria and Ephesus used the OT custom of laying on hands (e.g. Moses on Joshua, Deut. 34: 9) this seems to be an indication by the author of Acts that these were turning points in the progress of the gospel from Jerusalem to Rome. But by the end of the 2nd cent. CE the rite of Christian initiation included baptism in water, anointing by the bishop, and the imposition of his hand on the head of each candidate. However, by the 4th cent., the latter part of the rite became separated in time from the baptism: the large increase in the number of candidates obliged bishops to delegate baptisms to presbyters while reserving the second part, ‘confirmation’, to themselves.