The collect for today, The Feast of Saint Mark the Evangelist, from The Book of Common Prayer (Canadian, 1962):
O ALMIGHTY God, who hast instructed thy holy Church with the heavenly doctrine of thy Evangelist Saint Mark: Give us grace, that, being not like children carried away with every blast of vain doctrine, we may be established in the truth of thy holy Gospel; through Jesus Christ our Lord. Amen.
The author of the second gospel, Saint Mark is generally identified with John Mark, the son of Mary, whose house in Jerusalem was a meeting place for the disciples (Acts 12:12,25). John Mark accompanied his cousin Barnabas and Paul on their missionary journey to Cyprus, but Mark’s early departure to Jerusalem caused a rift between Paul and Barnabas, following which Barnabas took Mark on the next mission to Cyprus while Paul and Silas traveled through Syria and Cilicia (Acts 15:37-41).
Paul later changed his mind about Mark, who helped him during his imprisonment in Rome (Col. 4:10). Just before his martyrdom, Paul urged Timothy: “Get Mark and bring him with you, for he is very useful to me for ministry” (2 Tim. 4:11).
Also, Peter affectionately calls Mark “my son” and says that Mark is with him at “Babylon”—almost certainly Rome—as he writes his first epistle (1 Pet. 5:13). This accords with church tradition that Mark’s Gospel represents the teaching of Peter.